Besides the increase in performance, fps and graphics the only real thing that source 2 will change in competitive CS will be the grenade line ups since the the new engine will change basically everything related to physic’s :D
The granade lineups won’t change, they’re not related to the physics engine but rather pre calculated with specific integrals ahead. I think 3klilksphilips talked about it recently
I see no reason for the lineups to change, the usage might but if you want a grande somewhere you'll throw it like you did before (as long as they don't change the map)
With the things they showed, I don't think it's gonna work faster. Maybe for people with mid cpu and top gpu, but just the smokes, light and textures will need an upgrade on potatoes pc for sure