For street riding, sportbikes haven’t changed a whole helluva lot in the last 10 years. Most of the improvements in said bikes are seen on the track at high speeds. That said, what you’ll get with an older sportbike is a lot more weight. My friends mid-90s CBR weighed close to 600 lbs wet.
Honestly, if I didn’t love the track, I might not have a GSX-R at all. I’d maybe have a torquey naked (I do have my eye on those Triumphs…), but the track orientation of the gixxer is really a comfort-killer on the streets. The irony is that, among sportbikes, the gixxers are known for being “street-friendly,” and while I’m sure you can find plenty of sportbike enthusiasts that insist that they’re “friendly enough,” there’s just no comparison against a street-focused bike.
Listen, if you really want this, nobody but you is going to stop it from happening. You just can’t kid yourself about what you’re getting into. These are not easy bikes to ride, and the standard worry of straight-line power is NOT the main reason. If you’re up to it and you’re ready to put in the long, long practice hours required to become fully proficient at things like low-speed first-gear maneuvering, body positioning, smooth throttle application, smooth and progressive braking, etc, then you might consider a 600 or 750 made in the last 10 years.
I would not get a sportbike that’s 25 years old just so you can afford it, however. Trying so hard to force this issue should be sign #1 that you’re not able to see things objectively.