I mourn the demise, too. I hate tumblr. It's good for looking at pictures, but I hate the lack of interaction. It's just so... shallow. Half the fun of blogging/fandom, at least for me, is the commenting and interaction with other people. Just "liking" or "reblogging" something isn't enough.

As for dwindling fandom here, in the gentlest way possible, I think if you were still talking about X-Men (there's a new Wolverine movie! the next First Class is coming out soon!), you might get some more interaction. Which is not to say you shouldn't squee about whatever you want. You absolutely should. But I think your current interests are more of a niche that is better found on tumblr than LJ.