The funniest argument I hear against Blake is that he has never performed in the playoffs. He was fairly good in his first playoff run and was pretty terrible against the Griz last season due to injury.
Lets see his competition at the PF spot in the playoffs:
LMA: Never had a playoff run even nearly as good as Blake's first playoff run. For someone with such a great "jumper and post game" he never produced in the postseason even as second fiddle to Roy.
Love: No playoff appearances(not his fault for the most part though).
Davis: No playoffs but he is young.
Dirk/Duncan: both great playoff performers.
Outside of legends like Duncan and Dirk the rest of the PFs are bad playoff performers or never made the playoffs.