Perhaps Im not doing a good enough job of explaining the phenomena of an inferior individual talent producing better TEAM results.
Ill bring up some stats to illuminate my point.
In 2011 the Grizz made that memorable run, that season here is how the numbers (per36minutes) break down for the key members of the Grizz.
Now its one thing to put more pressure on your teammates to score, but making them both more prolific and efficient is something of true value.
With Battier on the court --------- With Gay on the court
Mike Conley: 16pts (48FG%) 13.5PTS (45FG%)
OJ Mayo : 16pts (3p% .45) 15.2PTS (40FG%)
Z-Bo : 22.3pts (50FG%) 18.6pts (48FG%)
Gasol : 14.2pts (52FG%) 12.6pts (52FG%)
So while Battier himself may be easier to contain, the intangible impact he has on his teammates is strong enough to offset that in most comparisons. And when your talking about someone whos played as poorly as Gay has this year, its easy to see why its time to move on. Even if Gay looks better in Toronto, I think he had enough time to make it work in Memphis, if it was even possible given their poor sets.
Basically, the reason Gay looked good (if you feel he looked good) was partly because he made his teammates look worse (in a comparison vs a truly efficient outlet option).