I would definitely consider that a serious potential issue, if for no other reason than so many communities will likely find a use for tags based on the nature of the community structure.
For example, I could see a ton of communities having tags for things like modposts, new member intros, meta topics, memes, questions, reviews, how-to’s/tutorials, guides, etc. and that’s just for broad post types that would apply to thousands of communities.
I think letting users manually make their own multi-lems, perhaps with the ability for communities to sort of team up to make uber-lems of closely related communities to help users discover more of them…but sub, unsub, multi, and un-multi as they see fit…is likely the best approach.
I don’t think there’s an age cutoff, or even a strict limit of social acceptability, but I do feel like the older you get, the less time people your age will devote, on average, to gaming…or at least the less focus they’ll give gaming.
It’s not necessarily a bad thing to still be super into video games in your 40s or 50s, but since there will be fewer people your age as invested as you, this will stand out, and one should reasonably expect this to have an impact on how some age-peers view and interact with you, for better or for worse.
The fact that a focus on gaming is more prevalent in kids than adults may carry the connotation that someone has failed to grow up in other ways as well, since they never moved past their gaming phase. It’s not always accurate or always negative, but subjective opinion might be both of those things.