Honestly with all the changes in combat system it would be nice if we have accessible both variants of morphs so we can switch easier and experiment with builds, also switch from PVE to PVP.
An "on the fly" changing of morphs? Honestly wouldn't mind but it does almost entirely void the point of respecs at shrines and scrolls.
You would still use shrines for skillpoint replacement, but the morphs which are needed for respeccing would be free and on the fly.
I don’t think ZOS would embrace losing the gold sink for respeccing morphs ... much less the loss of crown sales for respec scrolls.
Personally, I think choosing morphs adds to a character’s theorycrafting complexity. Being able to switch on the fly waters down that choice ... allowing players to not have to think about their character build.