Thanks for the feedback, Chris-ModaR.
I now see the excess fabric sagging the back of the thighs. I think it's because I have a flat rear and the suit was made for the average guy that actually has a backside. Maybe a tailor could remove that excess fabric in the seat?
There does seem to be excess fabric in various places: on the sides, back, and the sleeves. I'm rather thin so OTR clothing is usually baggy to varying degree.
I'm wondering if a MTM would be better for me? I like the suit but it seems I'll spend quite a bit altering it to fit my lanky build.
You have a flat seat, combined with trousers being too long, you need to adjust the rise and width of the back.