Yeah, let's just discount the majority of the season because it doesn't reflect well on him.
'13 Randolph wasn't near the player he was in '11. In '13, he was not all the way back from his knee injury. Also, the downgrade in shooting from Battier and Mayo to Prince, meant he had virtually no room with which to operate.
It was still an outstanding job by Splitter (and Duncan; they took turns on him and Gasol, yet somehow Splitter got all the credit), but again, just about anyone would have looked better given the difference in cir stances and options in '11. McDyess was practically retired and Bonner and Blair were Bonner and Blair.
Something else to consider about Splitter and Aldridge defensively, is Splitter is a 20-25 mpg player, who even in the playoffs could barely effectively log high 20's; Aldridge will play 32-24 mpg and can/will effectively average high 30's in the playoffs.
Not really. West was fine when surrounded by the solid - elite defenders that comprised the Pacers starting lineup during his time with them, but the Spurs bench is pretty much the exact opposite. He'll also have to play out of position, which in terms of 1-on-1 defense, they can probably get away with in most match-ups. The problem is neither he nor Diaw can defensive rebound or protect the rim.