User blog comment:Miskos3/Fairy Tail Episode 255: Tartaros arc: Steel, Review/@comment-5303512-20151017142819/@comment-7418318-20151017160733

Romance is just one of the differences in preferences, not the only one.

I imagine that for shoujou readers combat prowess is less important, which would certainly shift favour away from Erza, since combat prowess is pretty much her defining characteristic.