Oklahoma wouldn't trade Perk for Bass. He is too valuable. What Perk brings to the table with his physical size, toughness and post defense is more important to Oklahoma than what Bass brings with his two point jump-shooting.
As for Boston. I think it's a lateral move. Just switching current problems for different problems. Bass' lack of rebounding and dodgy defense for Perk's slow feet and limited offense. I am pretty sure Doc would put Perk back in the starting lineup too which would be really bad for that starting unit. Way too slow a frontcourt with Pierce, KG and Perk.
Not a good trade for either side.