Actually my problem isn't so much the basic look, it's with how... cheap and generic it all looks. It looks like he got his outfit at a freakin thrift store or something. I mean, those pants are just awful. lol
That's kind of the entire point you seem to be missing.
It's been lost in the drive to make Tennant look "cool" and "trendy" but the Doctor is supposed to be someone who doesn't care what he's wearing.
It's not necessarily that the Doctor doesn't care what he's wearing (try telling that to the Third Doctor!), but that the following personality generally goes against the grain of his previous incarnation. Thus, where Tennant was the slick, pretty-boy, Smith looks to be the awkward geek. It's the same with pretty much every incarnation, to an extent...