I just did some math and looks like the changes are actually nerfing LL's damage on single target.
patch 4.2
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LL base damage 200%
15/30% increased base damage from talent 30%
FT on off hand 40%
from glyph 20%
5x 20% for each searing totem stack 100%
TOTAL 390% off hand damage
patch 4.3
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LL base damage 260%
no increased base damage from talent 0%
FT on off hand 40%
from glyph 20%
5x 10% for each searing totem stack 50%
TOTAL 370% off hand damage
So it is a flat 20% nerf?