GSP L&P? Not really.
You do realize that over half the fight was stand up? Right? That would mean Diaz had almost a whole regular 3 round match to fight 'his fight', and still got totally taken to school.
When Diaz wasn't turtling, GSP was G&Ping, not L&Ping.
He got out boxed 40 to 103 in significant strikes landed, and 80 to 210 for total strikes.
You should watch the breakdown if you really think GSPs black belts are wasted ... JJ is not just about offense. Like any martial art they teach both offense and defense (many actually put more emphasis on defense,) so if GSP was able to defend himself against the supposed best WW JJ master in the UFC, then his black belt is certainly not wasted at all.