Here's a kinda personal question for you - how tall/big is your wife? I purchased a WTX before starting my cave course, and absolutely hated it by the end of the course. I think the smallest size available at that time was medium (which may or may not still be the case), and me being not so tall (5'2") and not so large (not telling), I ended up with flapping bits of webbing having to be tucked in all over the place, and the adjustment points so close together after being shortened up all the way, that I felt like I was wearing a bunch of buckles and not an actual harness.
Don't get me wrong, it's a nice piece of equipment, it just doesn't fit small people very well (unless it's available smaller now). I've replaced it with a plain old webbing harness and backplate.
Now I know that friends don't let friends buy jacket-style BC's, but if you are going to buy one, my beaten up old original Diva does in fact perform and fit a woman as advertised, and I still dust it off occasionally for single-tank dives, and I still like it. I imagine the model has evolved and improved since then.
But if I had it all to do over, I'd go straight to the wing.
My lovely bride is just 5' 2" as well but not a waif. I will say that the main straps had to be shortened a bit to fit her frame. She also had a Diva but loves the WTX Harness!