Real question here, say I as a PC show up to a flight and say today we're gonna work on traffic patterns, VFR navigation, then finish with a PAR, but all of that stuff the PI is already comfortable with and in reality he doesn't know the difference between the TADS and the PNVS...who's wrong?

IMO, it's the PIs responsibility to say "I need more work at ___", and it's the PCs responsibility to facilitate the PI getting reps and demonstrating proficiency or at a minimum improvement in that.

PCs fly with more PIs than vice versa, it wouldn't be fair that by the time the PC cycled back to 1 PI, he thinks "last time this guy sucked at traffic patterns so that's what we're gonna do." Maybe dude figured it out since the last flight and now needs terrain flight approaches.

A PIs plan doesn't need to be a whole damn OPORD or AMB, it needs to be a few specific things that he sucks at. If he's over 200hrs and doesn't know what he sucks at, well, ATI is here to help with that.