Not sure I'd agree with you there. I think there was a marked change in attitude/resiliance last season. After our horrendous start, we did well to haul ourselves back into the mix - and we showed more heart and togetherness as a team.
Liverpool toiled, and Spurs had an Arsenal-like implosion. We were different.
Now there's no doubt that mediocrity seems to be tolerated by our manager more than others, and that in the past, the team has lacked the mental strength to perform consistently. But I wonder whether both these attributes are down to over-committment to developmental players rather than some fundamental training flaw emanating from the manager. After all, going a whole season unbeaten takes mental strength and fortitude, and we had the same manager then.