I am almost willing to bet the new HRC will have a Nexite deck instead of a steel one. Not that is a bad thing, the one on the HRX mowers holds up really well. It might just be an HRX with an upgraded drive, wheels and engine.
If they are an improvement over the old HRC216 I might pick one up. I am a sucker for commercial 21 inch mowers.
2006 Ford F150
2013 Exmark Turf Tracer S Series 48
2013 Exmark Commercial 21 X Series Kawasaki BBC
2012 Exmark Commercial 21 S Series
2013 Echo PAS-280
2013 Echo PB-770T