Those wins aren't spectacular. None of them are top guys. Although the way Belcher won against Palhares was quite impressive, Palhares has never been a top MW. I am a huge Cote fan, but that guy hasn't looked good since he tore his ACL against Silva awhile back. And Gouveia isn't even relevant in that division at all.
I am not saying Weidman has the more impressive resume, but Belcher hasn't even beaten a top 5 MW, so I can't say he is #2.