Here's my concern with Alex Smith...I don't believe he is a big time QB that can make a team a title contender unless everything else is in place. He is a very good, fairly safe QB, that is better than most people used to think. However, I trust Harbaugh's judgment and if he felt that Kaepernick with his limited experience was a better choice (and so far it looks right) then why do we think Smith is the answer for us? I'd rather Kelly get a good look at Foles and decide if he is a guy we can do real long term damage with (in a good way) and I think the best way to get that answer is to play him. Smith is a good choice if that is one of the last pieces to help you go far in the playoffs. I don't believe we are there, unfortunately.
If we had a more decisive and impactful defense, and a good OL we could trust, I could get behind the Alex Smith idea. Right now though it seems we don't. (And hell, going back to my first statement, it seems that SF has that and he STILL wasn't "the guy.")