I thought it was EA's decision to pull out due to Valve's ToC changes(?)
My thoughts really were around the thing turning into a devilishly horrid fiasco when people acquired content in legal ways that made for logistic nightmares when re-installing. Fallout3 via Steam with DLC bought through GFWL being a prime example. God, I wouldn't want to be in the middle of that either way.
My impression was that Steamworks handles more than just cheats, but also handles achievements, networking, various chat modes, and in-game purchases.
As for Walter's comments, well, I'm just guessing he meant to say that supporting a game without Steamworks or steam running DLC is more of a PITA than one that does, in that Steam ends up taking blame for things that (generally) aren't their fault. Just guessing, though.
If I'm off on this, my bad ;-)
^D^
"Never start a fight, but always finish it."