If Seraphs were made unwish-for-able like their Gath cousins, half the end-game strategies people use would probably collapse
Here's a wish for you: I wish that we had about a dozen or so units that you could *only* get by Wishing for them, that made really good SC chassis. That way, you'd see more Wish variety at the end-game.
This might even be possible for us to Mod in...