I think one of the things I dislike most about Demon Hunter is how limited it is in terms of, to use Blizzard's term, "class fantasy."
Like... they are ALL elves, the ALL have tattoos, they are ALL blind, they ALL use glaives and only glaives, etc. There are various different incarnations of all the other classes, but with DH they are just pretty much clones of Illidan. I know that's established in the lore, but it just makes for a pretty flat seeming class that I'm not that interested in.
Even Death Knights and some others which are kind of.... lore-limited still manage to have some pretty decent variety. But Demon Hunters are just like literally all the exact same.
And the whole ultra-serious tone is really stupid too. Played a couple levels with one and yeah, the mobility and stuff is fun, but it's not something I can see myself getting attached to.