Just need to get more pressure in the backfield. Not sure why we haven't, whether it's effort or technique. Takitaki was a monster, but no one else really made any noise (Kaufusi did occasionally).
I suspect the lackluster D was part of the same problems on O: lack of effort and lots of mistakes. Seems to be a culture problem overall. Not Tuiaki's responsibility per se, except in his role as position coach (DL). I'd like to see him give up his DL coaching responsibilities next year, but if the culture can be changed, I think both Tuiaki and Detmer prove to be far better coaches than they showed this year.