I think you are just really turned off by the four strokes for some reason. Really, a 450 powered performance orieted machine would be in my garage. Not the first year, but the very first model of the second year. This is coming from a 2-stroke guy.
The 650 motor is lighter than either the DS or the Raptor's motor. If Honda built a "modern" chassis for that motor, the weight would easily be less than a Raptor. Probably rivaling that of the Cannon at 350 lbs. My R comes in at around 328-330 dry. I could accept that. Stock, the 650 makes like 55 ponies. SO WHAT if it is detuned for a quad chassis? You add your pipe and K&N anyhow, right? It will run down a quadracer in a New York minute.
I am not bagging on the quadracers, but the fact is the early versions were not as good as the 88-92 models. Even then, they didn't handle the rough stuff very good. My money would be on the big machine almost anywhere. I really don't like riding tight woods anyhow, so I could care less if it doesn't do well there.
As for the 450, the bike weighs 12 freaking pounds more than the 250! Yea, I could definately live with Honda building a machine worthy of that motor.
One last thing, go for a ride on a 250R (TRX). You may just fall in love.

 

I'm guessing that the 650, which from what I have seen from Dyno charts makes 45 HP at the rear wheels, when de-tuned would be about where the raptor is at the rear wheels, around 37HP.