With respect to Love, I don't buy that it's mostly a mental/clutch thing. The guy has some real significant physical limitations as an interior player, period. Defensively that is pretty clear, but it is true on offense too. I still can't get over his 36% field goal percentage on layups (shots from 0-3 feet) in last year's playoffs, on a significant sample size. He actually had a lower shooting percentage from 0-3 than from three point range! That is quite rare even for guards. He has such good technique rebounding that he can still be a very effective rebounder despite his limitations in terms of length, quickness, and leaping ability, but I still wouldn't count on him for a specific key rebound late in the fourth against stronger interior players.
His physical limitations show up more strongly and his superior technique/smarts matter less when the effort level amps up, and that is in the fourth quarter and the playoffs. At those times his arsenal becomes more limited and he can end up looking like just a spot up three point shooter. With that said, his three point shooting has actually been markedly better in the playoffs than the regular season for two years running now, and that says to me that this is not an issue of being a bad player in the clutch.