I hve been watching this thread for a long time. I used to go to SFStL several times a year until 1993, when a job change make it necessary to drop my visits ( I had season passes since 1983). I returned to the park just recently and would like to give my opinion compared to the 80's and 90's.
The park HAS changed, but not as bad as others have posted. It is not the same as before, but time moves on and things change.
Six Flags has kept a lot of the charm of the early days, but time requires change and the economy is not the same as in the late 80's/90's.
Here is what I noticed the most.
First, they FINALLY got rid of Hannabarrels, but the replacement could have been better themed to the location.
Ninja needs a good overhaul by either Vekoma, or someone who understands steel looping coasters. I don't remember the Ninja of the late 80's being this rough or loose (the train shuffles a LOT more than it should). The trains look to be the originals and they need a good bit of TLC, or replacement.
River King has been somewhat neutered, probably due to the lawsuit tendancy of the public. The support system looks like it could use some new wood, and the lift hills are rougher than I remember.
Tidal Wave is still a good, reliable, re-ridable ride, but looks stuffed in next to Boomerang because they stuffed Boomerang into a space that is really too cramped for the ride.
Moving up to Screamin' Eagle...Well, to be nice, it is still a good woodie, but the banking and changes to the back end took away some of the original feel of the ride. The changes didn't really hurt Eagle, just changed it. I still consider it a real John Allen gem.
American Thunder is a good ride, short, compact, and, the day I was there, not being run well. I don't blame the crew, but something was not working right with the blocking system and they could not send a train out until the previous one had totally stopped on the holding brakes before the station. I asked if they were holding the dispatch and the operators stated the system was having problems and Maintenance could not figure out why, but they were working on it. Acceptable knowing what I know about Process controllers.
Justice League.... Well, considering the age of the old water ride this is an improvement. Some effects were not working but then the old Tom Sawyer/Time Tunnel/Castaway Kids (never rode Scooby) always had effects not working.
My final review: SFStL has changed, but is still a good park with the same problems that all parks have with maintenance, upkeep, and improvement. If I lived closer to St Lous, I would still go several times a year. Do they need new rides? All parks can benefit from changes and replacements of rides. They don't have to be NEW rides, but rides in good condition with reliable history can benefit any park.
I will state this in negative terms. Grand Carosel DOES look bad and poorly maintained. SF needs to get a good restoration expert in to work on it and make it great again.
That's my opinion: mine alone.