Not a great deal that is novelty in terms of off-the-shelf here; the undercarriage, seats, engines and avionics are, but the rest of the airframe and structure are new or restressed ( the wings - CitationJets don't tend to carry ordnance ). A pretty standard mix of re-use and new development for second-tier types.

For nearly 100 years the axiom in fighter development has been: never a new airframe and a new engine at the same time. All this does differently from the F-35 is obey that.

It does look useful, sort of a sub-Northrop F-5 for the new era. The KAI T-50 and Aermacchi / Yak M346 would be in the same category, though a little more performant; obviously their marketing departments aren't quite as aggressive as Textron.