This question leaves me almost as "frozen/short-circuited" as just trying to think up what Hub to write has for quite some time now.
I have two accounts (my previous/pen-name one that was once my main account, and this one). I've got the other one hacked down to skeleton with nothing but the dregs that I can't/won't delete for some reasons; and I have this one, which I've also hacked to nothing several times but which never had all that many Hubs in it at one time anyway. Regardless of user name, I'm the same user who has been on here for about eight-and-a-half years now. The reason I ended up coming here and staying was that the many other sites on which I had written had, before but particularly after the first big Panda, gradually started aiming to "article-ize" themselves and content by trying to turn everything into something that looked like (wasn't necessarily) a professionally done article. (We have all seen how that "worked out" (?) for all those sites (because when all is said and done if your content is trying to compete with authority sites that content had really be super-duper unique, completely, and far more/better/different than what's on authority sites. )
While HP's previous "flexibility" with regard to content meant that much of my stuff was far, far, too casual and "off-handed" than really deserves to be found by someone searching, I've never been here to write on a professional basis. I've been here (more then than now) to get away from doing that. And, I've been here to take a break from "the rest of life" too - and just be able to write what I thought my worth writing about.
I have a handful of written things that would make a good, professional-looking, article (and another bunch of ideas/partially done stuff); but finishing those to make Hubs isn't "taking a break" from writing/day-to-day life.
My subjects don't lend themselves well to a bunch of glossy pictures (maybe readers wouldn't mind, but I imagine if there's ever a niche for them at all HP may mind).
I don't plan to specifically aim for a niche or on an existing-niche-friendly subject. Personally, as they are now, I see the niches as HP's "nice way of doing very well by articles that really do deserve their best shot at search traffic while clearing them off the main site where "human browsers" could once find something to read that interested them.
The question is what, if any, plans are there for the main site. :/ So I remain half frozen/half-baked.