Good luck to Karmichael Hunt and hope he is successful, whether it be in the AFL in the short term or Union/League in the long term.
From his point of view, he has achieved just about everything there is to achieve in the NRL, and wants to challenge himself by doing something he thinks he can be good at.
Of course it will directly affect the Broncos and their fans, but they have shown in the past they can attract great players and should get over his loss quickly. Not wanting to play against his Broncos teammates also must have weighed on his mind and influenced his decision.
Certainly GC17 have taken a calculated risk by signing Hunt, but the upside definitely out weighs the downside. If it doesn't work out, GC17 will have it's tail between it's legs, not the AFL.