What do you mean by succubus? As a player race, unfortunately not an option in 5e (yet) so would be homebrew. I'd definitely like 5e to finally accept and add traditionally evil options as player races like Gnolls or fiends. As an enemy, sure, but I think it should be at the right time. Just shoving one in would do a disservice. DAO I think handled them really well, sprinkling them in throughout and having them be a different challenge from other demons. As a summon, we'd need higher level and I don't think they count for either Demon or Devil summoning lists unfortunately, so I don't think they can be summoned weirdly enough. And if you mean Mizora, she's just a cambion but I kinda hope she'll be a non-origin companion and that her and wyll,'s relationship get more complicated.
