Holy is more than fine for LFR or 10man normals.
Disc is OP atm and gets nerfed in 5.2 anyways, also H.Paladins are pretty good as well.
Most healers are pretty balanced overall with some fights just leaning towards a specific healer (whole HoF leans alot towards disc tho).
Holy only needs a slight buff in mana regeneration as throughput is good enough compared to otherhealers, but once you get familiar with ur friendly blue bar than there is no issues on normal diff.
Just go with it.