I think Hotaru is awesome. I like his armour with the flags, his naginata, his white eyes and hair and his authoritarian demeanor. For me it's interesting how a character centered around law and order is willing to side with someone like Onaga, like a twisted way of understanding "order".
I have my own fanfiction (lmao) where he gets extremely angry after all the chaos the Outworld, Earthrrealm and Netherrealm have been causing, that he decides to take matters into his own hands and wants to spread order across all realms, starting by invading Edenia.
If Hotaru is someday in a MK, Havik should be a must.
Regarding DLC in MK11, if there is a chance of having 13 characters, I suppose there's room for Mileena, Shinnok, Rain and Fujin. I'd like Tanya to come back too, but it seems like the most far fetched, unfourtanely.