I love my 2015 bike
It is too much to use the last 20% of the performance most of the time on the road.
Wide open throttle with 10,000rpm + is pretty alarming the first few times and can only really be experience in 4th & 5th with a nice quiet, straight bit of road and good weather conditions.
If you do have the skills and judgement to do it justice, then why not? The great handling, brakes & rider aids make it relatively easy to ride.
My GSXR 750, which is, as has already been said, plenty fast enough, has been my track bike for the last few years. I can certainly use much more of that bikes performance on circuit than I could the S1000RR.
The S1000R is also a great choice. I had one for 2 years immediately before the RR
They actually have more bottom end & mid range shove than the RR. Absolute hooligan machines.