I agree, a 3wt is really all you need. You go fishing for fun, don't you? You might catch a couple more trout with a treble hook and a cheese ball on a heavy spinning rod with 10lb test, but a nice trout caught with a 3 wt is always a wonderful thing!!
I've fished with 7', 8', 8'6", and 9'. The extra length is so much better, even a UL like a 3wt.
Now you've got me excited to build a 9' 3wt for next year. LOL

Always catch & release,
Longrodder