Horford also plays in the East. How much would LA dominate the East?
I don't know. How much is Kevin Love dominating the East? I don't think the difference for a full season on a player level would be as big as people assume. For example, the average defensive rating for the east is better than the average defensive rating for the west. Where the West kills the East is on offense. You might say part of it is because of them playing more against lesser competition, but I think on the whole the difference is not big enough to expect much better performance by individual players moving to the east.
edit: I just checked his stats vs East conference and vs West conference teams. Here's my findings for his career:
vs East: 35.6mpg, 19.7ppg, 8.7 rpg, 2.0 apg, TS% .543
vs West: 35.4mpg, 19.2ppg, 8.2 rpg, 1.9 apg, TS% .525
While playing in the West his career averages are: 35.5mpg, 19.4ppg, 8.4rpg, 1.9apg, TS% .532
If we assume he played in the east and extrapolated his stats(52games vs East, 30 games vs West) we'd get: 35.5mpg, 19.52ppg, 8.52rpg, 1.9apg, TS% 536
As you can see the difference is negligible.