As an occasional dipper of the toe in the superheroic world of Marvel, surely the upshot of this is that the Sentry can finally be put to bed? He was interesting for all of five minutes when Paul Jenkins ripped Alan Moore's Supreme off lock stock and barrel, but since then has been a horrendous character whose main claim to fame is that during the World War Hulk event he did absolutely nothing at great length.
Well I suspect there are problems.
Marvelman isn't innovative or ground-breaking (or necessarily that interesting) - he is just a flimsy Captain Marvel rip-off. What is interesting is the story and the fictional universe and you can'r just shoehorn that into the Marvel Universe, Earth 616 anyway, - it could obviously be slotted into the Marvel Multiverse (because, technically it is part of a wider Comics Multiverse that also includes the DC Multiverse, the 2000AD Multiverse, etc.). There are some stories left to tell around the edges of the Marvelman Universe, Gaiman has a couple left to see the light of day (one is pretty much done, the other still needs the script finishing but the art is done on what is available) but beyond that it might get a bit stupid, unless someone with some serious talent comes up with a new angle. I think the best Marvel can do is finish the stories, get a fancy reprint out and leverage the property into other media (you could get a solid trilogy of films out of it).
You could get the character into the Marvel Universe through an alternate version but I suppose if they were going to do they could have him becoming bored with having created a Utopia and goes on a multiverse-spanning jihad. He could then pop into the Marvel Universe and starts making a better world and probably squeeze The Sentry's head like an orange to demonstrate how tough he is. He eventually realises that this might not be a great idea and buggers off home again having learned important lessons

. It could be a bit rubbish unless they get someone impressive in (like JMS) and they'd need to move him on at the end of the story because, if The Sentry proves anything, Marvel doesn't need (or apparently want) a vastly powered being, as they've spent their time hobbling The Sentry and making him into a bit of a joke.
So yes, sort out the reprints and I'll buy one, take the character further and... well we'll see. Someone might come up with something clever but unless they do then the Moore/Gaiman Marvelman is the only one I have any interest in, and personally, I don't think they can spoil that with whatever their future plans are because I won't read it unless it is really good.