I'm indifferent on Cooks. For most of the season, they've had all 6 WRs active on gameday. Chism hasn't looked very impressive as a returner though so I have to imagine someone else could do that. They could cut Chism and sign him to the practice squad (I doubt anyone claims him) and give Cooks that 53 man roster spot. He (Cooks) looks like a shell of his former self obviously, but he's playing in a bad team situation Williams has looked awful on a good team situation so far. I find it hard to argue that Cooks couldn't be an upgrade over Williams for the rest of this year, however marginal an upgrade that is. It'd be a one year deal so Williams can reset in year 2 - it's not a death sentence to his career here by any stretch.
HOWEVER, I do think we're talking pretty marginal improvement and maybe it does click for Williams over the next 7 games if you keep feeding him opportunities. His upside is higher. Hollins is playing like a pretty competent WR3 and Douglas is playing well enough to be a solid WR4 right now so we're talking about a clear WR5 type of role here. I don't think Cooks overtakes any of those guys, so maybe better to just stick with Williams getting scrap snaps in hopes of a breakout, however unlikely that looks for this year.