Certainly, last night was an aberration for Semih - but I didn't like him being essentially given away last year, certainly not with all the injury issues we had at the 5. I do think he can develop into a decent, rotation big - ideally your fifth big man, but someone who can play a little. Liked that he was able to run, seemed to have good hands and a decent feel for the game. Too lithe to ever play too much in the post, and wouldn't expect him to be an above-average defender or rebounder - but should be passable in those areas.
Of course, the fact that Semih's replacement (Troy Murphy) was completely useless makes the trade look worse.
Given the dropoff in Steamer's play since early on, I wouldn't mind having Semih on the roster right now - he'd help. Still, he's not a difference-maker.