How does Cessna 750 grab you?
They probably wanted to accentuate all of the improvements while emphasizing that the plane is still the Citation X (pronounced Ten). They could have called it the X+ or the XYZ. Like the Sovereign, they could have gone with Supreme or Imperial. The next edition will probably be The Ten+ so you have about four years to prepare yourself.
I’m fond of the 560XL, a 650 (III, VI & VII) fuselage mated with the wings and tail of the 560 (V, Ultra, Encore, Encore+) upgraded with modern engines and avionics. They called it the Excel (get it?) then the XLS and now the XLS+. If they followed Sikorsky marketing the next editions will be the XLS++ and then the XLS+++.