Re: I give Westbrook + get Ty. Evans & Jamal Crawford
I wouldn't do it. Westbrook has looked like a beast this year and will be in the discussion as a 1st-2nd rounder next season (this is coming from someone who isn't high on him, having seen him playing live at UCLA).
Westbrook has huge impact on FT%, assists, steals (and boards for a guard).
Tyreke is much better as a player in real life than in fantasy. There isn't a single thing he's doing better than Westbrook so far this year (except fewer TO's). Jamal Crawford is solid but is having an off-year and probably isn't someone you would consider keeping.
I would definitely keep Westbrook, since it's basically Westbrook vs. Tyreke in a keeper league.
By the way, how deep is your league and who's on waivers? Some of those players are unreliable for roto: Cousins, Favors, Blair, Bonner.