For track days and "sport riding" you're fine(your bike was rated highly in it's day). 99% of the riders out there can't use an EX500 to it's full potential, let alone a 1000.
To answer your question about the differences between yours and the new generation 1000's..
You couldn't dump $5k into your bike and make it on par with the new R1/GSXR etc.. They're about 100lbs lighter, have 20-30 hp more (stock), have better suspension, and better geometry.
Having said that, refer back to my second sentence
YZF 1000- about 500lbs wet, 120hp +/- at the wheel
R1 (2002) about 400lbs wet, 135hp +/- at the wheel
GSXR 1000 about 400lbs wet, 142hp +/- at the wheel
IMO, neither the R1 or the GSXR belongs on the street. To think that any 18 year old squid(without any prior riding experience,) can pop into a dealer and plunk down $10k (or finance it), and ride out on a 180mph rocket is ludicrous.
These idiots that read all the hype about absolute horsepower
, and have to go get the baddest to show up their friends, are going to be the demise of motorcycling. O.K off my soapbox now..