Perhaps the question is not should he move on but if he did who would produce the returns he does? Unless we have a bona fide replacement waiting in the wings then statistically he produces.
Much like the team itself there has been a gradual reduction in consistency not just with Sinclair .
Given that first season for almost every player was above and beyond what could conceivably be considered as likely to be consistent, then maybe we have to ask if what we ask of the players is reasonable.
Perhaps if our own expectations are unreasonable then it would be fair to assume the players may feel the pressure is indeed unreasonable also.
It's possible we are just seeing players levelling out a bit.
Maybe Lenny will inspire improvement by some tactical alteration (if he keeps the job) next season. Given what Sinclair's stats return even in poor form in such a slump, perhaps the future changes will see him step up again. One more year is no risk to see if this may result.