I had a 03 WR250 which I rode extensively in GA and TN. I hadn't ridden dirtbikes for 20 years and was afraid of getting something too powerful for old dude.
It was fine for the first year as I got back in the groove. I rode it for another couple years and had to "wring it's neck" to get the power I needed to ride aggressively.
Then I moved to CO and felt like I was on a freakin 50cc minibike. It was so underpowered it was almost dangerous to ride.
So I plopped down the money for a WR450 and this thing is better than sex. If you are worried about too much power - don't. Get the free mods done and get it tuned for your altitude, etc. Get them to tune it for better off idle response and all your dreams will be fulfilled.