After watching this thread and the one at the 250 prod group on Yahoo rage all day figured I might chime in.
A little back ground. I have ridden on and off for about 10 years and finally have a small bit of disposable income that I would like to spend on motorcycles, learning how to go fast, and possibly race for next season.
I just bought a 2000 EX250 and definitely consider buying the new one and using it instead for the 250 production class.
With all the guffawing about, well its not a full production "take the plate off and race it", it suits alot of purposes still.
After hitting Thunderhill this Monday, I was able to pass quite a few people on much bigger shinier bikes. I think for a couple reasons.
1.) I was never afraid to get on the gas, I knew the bike wasn't going to throw me off like a bigger one.
2.) Never had to brake that hard, I figured out that it was all about corner speed to try and fend people off the straights.
3.) The little bike is very comfortable I rode all day without really noticing it. Not something I cannot say for my 749.
At the end of the day the bike instilled alot of confidence and let me focus on my riding as opposed to fear of extreme speeds. I got on the throttle sooner, braked less, and worked on corner speed, all great skills that would carry to a larger class.
Things that weren't so great, 16" Rims, no modern rubber for my bike from the local Dunlop vendor :-(
All the advantage I had built up in the corners as other new riders were scared of opening their throttles was evaporated in the straights and the found their confidence in a nice straight line.
So what of the new bike?
Well to start its frickin' cheap compared to your next closest entry bike. Lots more money for tires, gas, replacement lever and clip-ons and glass body-work
It has 17" wheels, hey I don't have to spend $1000 on a now outdated bike if I buy the new one.
Better mid-range and low end ~45 horsepower, even if it ends up as 33 - 36 RWP , thats still competitive and I wouldn't have to spend at least 2k and lots of time to do it from the old engine. Fresh from the box its ready to go. New valve-train with less moving parts to wear. Plus a 2-1 exhaust for less weight.
Updated forks and new Double semi-cradle frame. Given that the current frame is basically a back-bone frame, they have had to do some massive redisgn. All the haters at this point say yeah but its steel! Well steel repairs a hell of alot easier than cast aluminum, and keeps the cost down. The swing arm looks to have been made beefier. Also bigger rotors which would be less likely to warp.
The suspension, more could have been done here , but there are 1mm larger forks and as I read some where now there is at least preload adjustment for the rear shock. Not earthshaking but hey its better that before.
Appearance, yeah it looks better, but it also has better aerodynamics, and a windscreen that you can tuck behind.
Yes I am sure Kawasaki cleaned some of the parts bins with this bike, but since the 20 years it has been around the parts bin has gotten much better.
All in all this will be a great little bike to hit the track and probably a stellar bike for the streets with a couple things that the old Ninjas cannot upgrade such as an updated frame and bigger forks and a more reliable valve train. Watching the HP numbers creep up over the years I see no reason why this bike wouldn't be competitive.
You've got a good sense of humor, which is all cool. 
