Incarnate Info
Well over the course of just making one ability you'll make a few different versions of it, if you build toward a very rare, since they consume a pair of Rare abilities.
Actually the latest update fixed a problem with people having too many Incarnate powers of a given type (Alpha, Lore, etc) so you now indeed can have every single one. The fact that they went out of there way to allow this shows that they have not issues with it. You can still only have one slotted at a time, so there's no reason not to allow it.
As for me personally, I prefer to use the shard based stuff with alphas. I'm going to do many of those high level tfs anyway, so it's really not too hard to do at all. I may vary that tactic as needed, and once I unlock all the Astral costume goodies (I only have two or three left) I will be more likely to convert them to shards and threads.
My apologies Ninus, I must have missed that part when I read through, but after you pointed it out, I do recall seeing that. My bad.