I love Alex and agree that we can win with him too. But his recent numbers look a lot less impressive when looked at in this light.
My contention is that 4 out of his last 6 starts were incredibly mediocre. We'll take a look at those starts in detail below, but there are some other important facts. His 3rd down conversion rate for the season is 35.2% which would put the Niner's at 25th in the league (it may in fact be lower than that over his last 6 starts, and was 28.1% last year, SECOND WORST IN THE LEAGUE!). In Kaepernick's 3 starts we are 41% 3rd down conversion, which would put the team at 9th in the league. Now, Alex IS 4-2 in those starts, but Kaepernick is 2-1 in his starts (meaning the same win rate -- again the Rams game isn't fair to include for Colin since he took barely any reps during that week of practice). Alex also has more than twice as many sacks per game on the full season compared to Kaepernick (2.6 per game whereas Kaepernick has only 1 in his 3 starts). To be fair, Alex did do much better his first two games on the season, but he also did much worse for the whole of last year so this mediocrity may be more-or-less what we can expect. A good game here, followed by two mediocre-to-bad ones. All this is to say that I think that Harbaugh is making the right move in trying the new hand. Remember, he's trying it out -- not committing to it for life. If it doesn't work out, he goes back to Smith. Alex is a veteran guy and hopefully wouldn't have his confidence rattled if put back in.
These are the 6 games in question (with a chart from ESPN with the full stats for those games listed). When we look beyond quarterback rating, we see it's not such a pretty picture.
Min - He threw the ball 35 times and only had 204 yards passing. He had a good completion percentage, but a pitiful 5.83 yards/attempt average. He also had a pick and we lost the game.
NYJ - We won the game, but Alex had nothing to do with the win. He threw for measly 143 yards with only a 57.1% completion percentage. And his yards per/attempt ranked 26th relative to the average yards/attempt starting quarterbacks put up in the league.
Buf - He had a monster game. No ifs, ands or buts about it. Shitty defense, but he played supremely well nonetheless.
NYG - Disaster. 30 throws and only 200 yards. Pathetic 6.67 yards/attempt. And 3 interceptions.
Seattle - Another blah performance. Only 140 yards on 23 attempts, including an interception. Again, a pathetic 6.09 yards per attempt.
Ari - Excellent game. The stats speak for themselves.
[I didn't include the Rams game, because he didn't play much. But even then he had one really good drive, but one awful drive. Recall, he 2 sacks for a loss on 9 yards in his limited time on the field. In the four quarters that followed, Kaepernick had 3 sacks. And has had only 1 sack in his three starts]
The last two numbers in the column are ESPN's QBR Rating and the standard Passer Rating.
Again, all this is to say that I think that Harbaugh is making the right move in trying the new hand. Remember, he's trying it out -- not committing to it for life. If it doesn't work out, he goes back to Smith. Alex is a veteran guy and hopefully wouldn't have his confidence rattled if put back in.