Would a Kawasaki zx7r be a good choice first sports bike?

A CBR wouldn't be bad, those things are really reliable.
In all honesty though I've always had a thing for the 636, so I assume the ZX7 would be of the same build and quality.
Going from a Bandit, you'll be fine. Just keep that throttle light for a little while, it does have the guts to plant you on the ground.

If you've ridden a 600 bandit you will be fine on a zx7, as with any bike just take it easy until you get used to it.

Personally, I am not a Sportbike fan. However, since you have several years experience, this would be a logical progression.

A word of caution. Don't let your testosterone get the best of you. Since you have not been on a bike for a few years, take enough time to really get used to this bike before you start breaking the traffic laws. Isn't this why you get such a fast bike anyway? Be honest.

Yes I think the ZX7R is a great choice, I have had 1000's and 750's and I find the 750 to be the best of the lot, best power to weight, handling, and not to mention the ZX7R looks good too,
When I made the swap from standard bikes to sports bikes I had not really ridden in a year, if anything its good because it will take less time to get used to since your not still riding the Bandit until you get it, if you still had the Bandit and sold it and bought the ZX7R a week later you would still be used to the Bandit so it would take longer but since you sold it a while ago I would say it will be easier,
That being said of course it will take a little while to get used to anyway, I will give one bit of advice though, going from a standard bike to a sports bike myself there were really only two things that I noticed, first was the higher pegs took a while to get used to, if you sit on before you ride it it will be easier to get used to, the second thing was how the gauges and such did not turn when the forks did which was not a problem it was just something that took a little while to get used to, going from standard bars to clip-ons actually was never an issue for me,
Im sure different people will have different experiences of course I just though I would share the two things I noticed personally in case it may help you in some way,
Good luck and I'm sure things will work out well.