I am guessing that you are a recreational-type skier? Don't ski long line on a tournament boat -- it's just not right.
At 15-off I don't think you will find a better wake than an American Skier. I can't speak for an '88 in particular, but my '84 has one of the smoothest, flattest wakes I have ever seen at 15-off. I ski with a number of (tournament) skiers, and have never heard a bad word about the wake on an AS.
At 22, there is a bump. I spend most of my time from 28-35 off, and my AS is very nice. 35-off+ will get you into spray on the older boats. I skied my '84 on Tuesday, and a 2012 Nautique Thursday. From 28-35 off I'd take either, and be very happy.
Todd