I bring it up because people get bored easily and start looking for the next new hook or big thing.
I enjoy the films and the shared universe. Hell, personally, I'd like to see a little more crossover between the different mediums; let's get Quake a cameo in a movie, or have Panther show up in Luke Cage! Personally, I hope that when Agents of SHIELD is cancelled (whenever that happens) some of the cast is able to continue the roles in film.
I dont think its an immediate concern and I certainly dont think it'll be a consideration in time for Panther, but the novelty will wear off at some point. Hopefully that day is a long ways off. But when it does hit and Marvel (along with DC) realize that the shared universe isnt as much of a pull as it was, I hope they have something else planned to keep people engaged.
As for Panther, I dont think anything is going to ruin that film's chances outside of some huge scandal, like we find out a week before release that the director is into child porn or something equally vile. Nothing short of that is going to hamper the film, I think. Well, I suppose if every Marvel movie between now and then fails in a spectacular fashion, that would do the trick, but I dont see that as being at all likely.