I would definitely go with Glastron over Bayliner any day. Glaston hulls are top quality, Bayliner hulls do not have this reputation. In fact, I've heard they're cheaply made.
I must confess I know very little about the GTD but I can see why it appeals to your wife from a practicality/family point of view. Lots of seating space in the GTD. What I can see in the specs is that it's got a 6 inch wider beam, a flatter hull (2 inch less deadrise) and weighs approximately 465 lbs more than the GTS. It doesn't have the SSV hull either and you know how highly I recommend that design. Great ride, great ski wake, planes at lower speeds than most other boats, fuel efficient, really stable, handles well and rides the rough stuff really well.
With the GTS I know what type of overall and skiing performance you'll get and I know you'd be very pleased with that boat. I know nothing about how the GTD performs and skis so all bets are off there. The only way you're going to know how the two hulls compare is to try them both out and see what you think. It's quite possible the GTD will be great for skiing too, I just don't know.
What I will say is that whichever of those 2 hulls you decide to go with, put 150 HP on it (preferably an ETec). I have the ETec 150 HO on my GT 180 and it's perfect for that hull. Great hole shot, power to spare and terrific fuel economy. Either get the ETec 150 or 135 HO as they are both pretty much the same motor. (The 135 HO is rumoured to be 150 hp). Don't get a 4 stroke! They're way bigger, 100+ lbs heavier and have a lot slower hole shot than a 2 stroke. Between those disadvantages and the fact they have over 130 more moving parts than a 2 stroke, a 4 stroke kills every advantage an outboard is supposed to have. And of all the 2 strokes that are available, IMO the ETec is the best in the class. Remakably, the ETecs even have lower emissions than all or most 4 stroke outboards. That is quite an engineering achievement. I LOVE MY ETEC!!*
* Note here I'm talking about the basic ETec line. I've heard the ETec G2s are great as well but they're quite expensive.