Well personally I enjoy riding an older bike. It takes away a lot of the 'pressure' to ride fast. If you can't keep up, then hey, I ride an 11 year old bike. However most of the time I can, in which case it's all the more fun!
I was following a fella on an 08 Blade last year, kept up with him no problem until 90mph when I decided not to go any faster for the sake of my licence. He only got away by opening the throttle to prison-sampling speeds.
I have a mate with a 2000 R1 and he can't keep up either, despte a good 25-30bhp advantage.
I also have a mate who used to have a 2000 CBR600F and he would waste me regulary. I know a bloke now who rides a BMW R1200GS Adv and he loses me as well.
So basically IMHO the 900's are still more than good enough on the road. Any bike capable of easily doubling the national speed limit should be. I guess if you enjoy blasting down straight roads as fast as you can, then the new bikes might get you to prison quicker than the 900, but I don't ride like that. I prefer twisty, challenging roads and there the 900 is more than capable. Actually, for the sort of riding I do, the BMW GS is probably better, due to improved visibility. No need for more power in this situation.