As for your switching during a massive, that "bug" was fixed, you can no longer charge a massive while switching weapons, it will always cancel your massive. Other than this, over the period you mentioned, I have noticed no changes to the way timing for weapon switching works. Perhaps you have muscle memory one way or the other acquired from a different game that allows those instant switching. Stairs slipping is a known annoyance that gets more intense with unstable FPS and/or a high set FPS value. You mentioned that you capped it at 250 which is a good value, but notice how much more intense that effect is when youre on 1000 fps, on the floor too. There isn't really a solution, inclined surfaces are slippery in gunz.
