The odds are against Okobo being the answer, at least not in the near term. In any case the answer at PG is by no means the whole answer for the team - as you said, tenacity and muscle are greatly needed. At least the team is playing harder now. Holmes was a good step in the right direction but we need more and Harrell would have been a great pickup for us... much better than Ariza, for instance. Of course, on a one year deal it wouldn't make a great difference.
I'm in the camp of reducing Ariza's playing time, and his play was a surprise. It shouldn't have been because when I look over his whole career his offensive numbers have been dwindling toward what we are seeing - he's almost exactly on his career average numbers across the board. He seems to have fallen off on defense more than on offense but I haven't dug up his numbers for D, scant as they are.
Ariza's offensive numbers are very close to average among all SF's so he's not dragging the team down there. The guy who is dragging us down on offense, is Josh Jackson. Eliminate his offensive stats and the rest of the the main 9 contributors is actually close to the league average. His killer stat is turnovers and his shooting percentages are low.