I mean who wouldn't want to see a few new goblin-kin or dwarven deities? Everyone's heard of Khedrun's Vale so maybe there's a demipower or heroine who has a following etc.
Demipower or demigod works well enough so why change it? I'd also like to see a slew of demipowers added to the Realms for small cults, different takes on other deities etc. I'd like to see exarch not used in any form. another way of saying they were basically standard 3E characters in 1E, pretty powerful but not really demigods. Perhaps more accurately called "Super Heroes", same as other characters except for some perks (at least one stat 19+, no class or dual-/multi-class restrictions, sometimes a special/unique skill or power of some sort, often some kind of other-planar bloodline, typically small army of followers/worshippers).
I'd like to see more demigods in 5e, but weren't they "exarchs" in 4e? Quote attributed to Talor Stormhammer, paladin of Helm, when fighting a frost giant. It would add a nice mythological feel to things. In many ways, epic characters or particular angels and devils/demons are already on that power level. Someone, friend or foe, that is accessible for players. I would like to seem them fill that "middle ground," if you will. Good examples of this mentality can (or could) be seen in Drasek Riven, Gwaeron Windstrom, Bast/Sharess, Selvetarm and Gargauth. Their singular avatars are likely to sire aasimar or tiefling children among the populace in this phase of their divinity. Their relationships with their divine peers makes demigods quite hesitant to directly influence the lands of Faerun. They are usually found walking the grounds of Toril every once in a while even if they already own a personal domain in the astral planes near Toril. I'd use them as 'living' legends, as they are mostly from mortal origin. Traditionally Demigods have been more accessible then higher Gods.