I see your point, but it is not like 2013, or 2014 Carson Palmer was playing like he did in 2015. Now in 2016 he looks like the guy who we saw in 2013, and 2014.
Not saying the guy is not winning football games, not at all. I am 100% OK with Carson Palmer playing like.....well, Carson Palmer. I do not think Palmer is the problem, I think the problem is the team around him is not as good as the 2013, 2014, and 2015 teams. There ARE 21 other players that have an affect on the game. Yes, the quarterback is important, but there are still other factors.
Personally, I think expecting Palmer to play beyond what he normally plays like is a bit unfair. He is who he is, and that is what you are going to get out of Palmer.
I think there are a lot of players that are not even playing up to their normal level that are not the quarterback, and that is the bigger issue in 2015. IMHO.