The problem is finding a niche for him after all this time. Carol's got a lock on his name. Maybe they can do something like Odinson for him? I'm kidding!!!
There's no shortage of cosmic types (almost all of which are being ignored or misused). Does the universe really need him? Is Marvel sincerely going to enhance their cosmic stuff? They really don't seem committed to that. But let's hope, whether Mar-Vell returns or not.
Well his name is really Captain Mar-Vell but upon arriving on Earth, humans misunderstood and said he was Captain Marvel
Seriously though, Carol could keep the name especially since the impending movie is her as CM and not Mar-Vell. Mar-Vell is still Captain Mar-Vell and he can spend some time on Earth or when he is not needed dwell among the stars with Elysius, his lady love (presume she's still alive)
Still if the EIC states that there is room for the legacy and new versions, that includes Mar-Vell in my opinion.