Someone (I can't remember who... Hollinger?) had an insightful article that the problem with the Sixers was that they were struggling to incorporate Brand because they're just not equipped to play a half-court game. No one can shoot, and other than Miller they're sloppy ball handlers/penetrators (Thad Young seems like he can do either and is doing well this year -- Iguodala is struggling). They did well last year as a running and gunninng team and beat teams with their athleticism and finishing, but they had to slow things down and it has really messed with their offense.
And that's just a roster problem. Maybe a coach would be able to work it all out, but it's tough to incorporate mismatched parts.
That said, like Bricklayer, I don't think Cheeks has been that great of a coach. Totally respectable, and probably did the best he could with declining Blazers teams and turning the corner on a bad situation in Philly, but not someone who was going to work miracles. Still not a reason to fire a guy though.