To the original poster:
I currently own a 94 Four Winns Freedom I/O with a 4.3 V6 and am an avid slalom skiier. My ski partner owns an 05 Outback which I've spent a lot of time behind. The wakes are not dramatically different, but the Outback is better (as it should be). Here's a couple pics:

This is my I/O wake. It is reasonably flat but has a bit of curl that you have to cut through. This is at 22' off, 33 mph.

My friend's Outback wake. It is flatter, but it's not a giant difference. This is at 15' off, 33 mph.
I plan to purchase an Outback or other DD boat in the next couple years, but I know from skiing behind both that the difference isn't night and day. When I was a lot more timid crossing the wakes, his DD wake felt a lot better, but after getting more aggressive (on edge), I find the difference to be a lot less noticeable.
I don't think your observations were off on your test drive, but like other posters said, you should ski it before you commit to a purchase to make sure you get what you want.
Allan