I think Chris Eccleston could play a good Maxwell Smart.
 

I know it's currently moot, with a movie coming out and Carrell playing him, but Eccleston's got all the right mannerisms for it. If he could fake an American accent, he might well be perfect for the part.

I have not seen enough of him to judge. I think he would be great for it. Nothing against Steve Carrell, but the guy just seems "too funny" to play Maxwell Smart. I mean, yes, he's got very dry delivery, but everything the guy does is designed for a laugh, which just doesn't seem in the Get Smart style.

I think J.K. Simmons would make a great Chief. Dwayne Johnson would have been good for Hymie, I think.

But then again, I think Mel Brooks and Buck Henry would write a good Get Smart movie, so what does it matter what I think?