Maybe you have more information than I. I don't see any publicly available renderings or plans on HOK's site, so I'm going off the renderings in the NextSTL article, which appear to match what's in Biz and STLToday.
1a. Create a direct walkable path from the Foryth Metrolink to the office tower(s). Right now (contrary to your claim) the office tower does not front Forsyth station in Centene's proposal. A parking garage would. Pedestrians would have to essentially walk around the perimeter of Tract 3 and double back to access the office.
You misread my post. I don't suggest the office tower is adjacent to the Metrolink station. I said the primary entrance is. Unless they plan to move out of their current office tower, which doesn't appear to be in the works, they'll doubtless want to keep the offices mostly together; thus the new tower and garage directly adjacent to the existing offices across Hanley. I don't foresee upper, or even much of middle management riding Metrolink from their digs in West County. (Not much service out there anyway.) I do, however, think customers, guests, and staff might ride Metrolink. The station is half a block closer to the new office tower than the old. Still a walk, but if you can walk from the station now you'll be able to walk when they build the new tower. And the space for guests and customers (by which I mean doctors, hospital administrators, insurance providers, and so forth) is DIRECTLY adjacent to Metrolink. The plan makes it easier for visitors to use transit. And it makes it no harder for employees.
Your plan moves the auditorium a half a block further from the metrolink station. I think the term "civic auditorium" might be causing some of the misunderstanding. Given that it doesn't appear to include any stagehouse I'm assuming it's basically a meeting space. Nice meeting space, but meeting space; more of a classroom than a theatre. (A useful theatre will typically have a fly chimney that is quite visible and at least fifty feet tall; usually more when you move away from high schools. They tend to look a bit like a giant shoebox.) There's none of that in the rendering, so I'm guessing it's not anything like a performing arts space; just a large room with raked seating, a modest stage, and some good AV equipment. A meeting space. A conference room. A "gather round and listen while we wow you" space. It will be useful for press conferences, teleconferencing, continuing education, and so forth, all of which fit tidily into Centene's core business. They may call it a "civic auditorium" for marketing reasons, but make no mistake, it's a business space, not an arts space.
The medical industry is one giant conference after another: conferences about the newest drug, or the newest insurance plan; new software to manage patient care; sales pitches for gadgets and computers; continuing education for doctors, patients, and pharmacy staff . . . they will (and doubtless already do) have a real need for conference space. And there will be lots and lots of fancy customers there. Maybe more than a few of whom will fly in from out of town. And many of the rest will come from Wash U, Barnes, SLU, . . . places with good Metrolink access. But they'll have zero cause to go to the administrative offices. Employees will drive to the garages. Guests might well ride to the conference center.
And between the conference center and the residential tracts on Carondelet Plaza, what do we have? Mixed use. That will likely include some guest rooms, more smaller conference rooms, and perhaps also some retail. Guests like to buy stuff, after all. And they like coffee and maybe food. And sure, there will be a few offices there: a building manager, some service offices, maybe a hospitality office. Catering, perhaps. That sort of thing. Conference spaces mesh well with hotels and restaurants. Big players sometimes have at least a little bit of their own private hotel space. Sometimes even smaller players. And yes, there's some parking there, but it's back away from the entrance. And it's stage three parking, which means it's the piece most likely to change. There is one rendering that looks a bit misleading to me: it seems to show the parking garage directly at the corner, but others contradict it. I think what that is is more likely to be a lobby between the garage and the auditorium. The first floor will almost certainly be a mixture of lobby space, retail, and conference space connecting the hotel, offices, and meeting spaces. The garage will be above and behind that. It's an early rendering of the stage three stuff, and probably among the least detailed and fixed of what's on the site.
1b. TOD - Put some retail and residential near Forsyth Metrolink station instead of a garage and auditorium (probably inactive 90% of the time)
First, I bet you're wrong about your estimate of the utilization of that auditorium. I've worked in the medical industry directly, and I've done a lot of AV rentals to drug reps and medical administrators. I've done quite a few AV installs in lecture halls and auditoriums. (And indeed, in "civic auditoriums" and performing arts spaces.) You're thinking of a different industry than the medical industry I've worked in and with.
But getting back to the plans . . .
They don't want the residential right at the station. That's where they want their fancy guest spaces. Those spaces will BE exactly the TOD you want, but they won't be apartments. Apartments would be primarily for folks working at Centene. They don't need to take Metrolink a block to work everyday. They need it to go to a show or for a business trip. And they can afford to walk a block for those less frequent excursions downtown or to the airport or wherever. Apartments in the middle makes great sense. Garage fronting Forsyth also makes good sense. Thus the larger garage is convenient to residents in the apartments and guests in the conference space, and not too inconvenient to employees in the administrative buildings. And again, note, the conference space is between the garage and Metrolink, so you can get to the conference easily by either route. (I'm sure they'll get both.) The station is at Forsyth and Forest Park. The auditorium and mixed use structure is also at Forsyth and Forest Park. The largest garage is on Forsyth between Carondelet Plaza and Lyle. And in drawings you'll see what surely looks to me like first floor retail fronting Forsyth in that garage. Look closely at this drawing:
https://nextstl.com/wp-content/uploads/Centene-5.jpg
That appears to be the elevation looking east down Forsyth. That surely looks like the old Famous across the street. Doesn't really look like any of the towers on CP, or the Crescent. I'd say that's your street level retail. I think they have it covered. Seriously. Actually, in the more detailed renderings it explicitly shows the first floor or two in each garage being retail.
2. Provide space for pedestrians that is not a useless/inactive plaza, connects destinations, and provides retail space.
To some extent I think they will, but I think you misunderstand their aim. You seem to envision this as a single unified campus. I don't think that's what they have in mind. I think they see it as two separate campuses for two different functions: one for guests (or more accurately customers) and one for administrators. Which is to say one is providing the services and the other, the tall one, is the back office. To some extent they might connect them with residential, but there may not be that much direct pedestrian communication between the two. And I think you're making some assumptions about the garage that aren't founded in the plans I see. Why do you think there won't be street level retail? They already have street level retail in their existing garage. The newest several garages in Clayton that I'm aware of all have retail. Why wouldn't this one? The drawings show something that looks much like retail there. If it's not retail, what is it?
3. Try to reconfigure the mess of a garage superblock in Tract 2 with something that resembles a somewhat urban environment with buildings fronting streets.
First, the superblock is already there. Instead of an empty green lawn of a superblock they're planning to build a garage. I've walked past a lot of garages on a lot of campuses. I don't see a problem, especially if there're stores in it. Could they break it up? Maybe. I'd even guess there will be pedestrian access across it anyway, but maybe not automotive access. Do you really want the traffic flowing out the south side of the garage onto CP? That's what the residents are already worried about. Routing automotive traffic (and there will inevitably be more than a little) onto the major thoroughfare seems reasonable and natural. By keeping the bulk of the traffic off CP that should make CP more walkable, more friendly. That will sell better in the crescent than a plan that puts a major auto exit right into the thick of it. If I read their renderings right there will be retail fronting Forsyth and later residential fronting CP: appropriate buildings fronting appropriate streets. Given my druthers I expect I'd prefer to walk along what will be the shaded side of Forsyth next to Centene's garage and retail than the sunny side next to the bank and the asphalt parking sea on the other side of the street. I'm not sure how, but it's almost as though we're looking at different renderings. To be completely clear, this is what I've seen:
https://nextstl.com/2016/06/centene-unv ... s-project/
I think HOK and Centene probably have a very good idea of who will be using their buildings and why, and I think they've cited things appropriately. What they're showing there looks considerably more urban than anything there right now. It's dense. It's vertical. It's connected. It all looks very permanent and quite decent. Even the generally lower east end looks much more like a dense college campus than a suburban office park. I really think you misunderstand their plans. HOK is a darn fine firm that's done some top notch work. I think they deserve a bit more credit than you're giving them. The plans they have answer most of your back of the napkin objections if you read them carefully.