Solo is a 6/7 right now with occasional flashes of more. But those flashes are just that, flashes. Unless he goes to the AHL to develop those flashes to be more of an occasional or semi frequent occurrence at the NHL level, I agree that many teams have a guy like that.
IMO both you and
@Lunatik are correct, but Solo is sitting solidly in between both your opinions. Solo is at a calibre most other teams have, but Solo has also shown occasional flashes of potential that other players at that calibre don't really show. Clear upgrade wise, I agree he is not that on the Flames, but the Flames also have so many more guys that are 6/7 calibre right now. Solo could potentially be a clear upgrade on another team's bottom pairing, so I can see why Luna is concerned.
Even if we lose Solo, we have similar style guys in Kuznetsov, Grushnikov, Hurtig, Jurmo etc. But none quite at the clear 6/7 level as Solo and none have sorta shown something extra at the big club level like Solo occasionally has. I kinda understand the logic of developing Solo so he returns as a 4/5 calibre guy and maybe a solid #4. But I totally get the concerns on risk and I feel like he won't be able to accomplish that on limited minutes at the NHL level.
Others might not be worried even if such a calibre of player is claimed, but IMO I'd rather not lose Solo.