RE5 does not mix in a "weird, janky system". I played RE4 three times back to back in like the span of a few days just the other week. They're practically the same. The only difference is the fact that run and shoot buttons have reversed.
Chris is more slow due to a number of things: 1. animations; he has to stop and PICK items up while with Leon he automatically got loot when you decided to pick it up. 2. The aiming speed is slow as fuck, turn it to fastest speed, 3. Chris is more slow than Leon in general. Haven't gotten the chance to play as Sheva yet but being more slow does not change the controls a bit, since they're...you know, the same. I agree Chris is slow, but you get used to the controls in like 2 seconds if you have played RE4 for any length of time.
I wish we could have an RE5 discussion for any length of time without someone mentioning the controls. Sigh.