I'd like to suggest changing Astapor, Yunkai, and Meereen to being parts of larger De Jure regions. If you form the Empire of Ghiscar, the lord paramount mechanics mean that you can only control a very small region without a lot of busy work or tyranny. If you're playing as Daenerys and form the empire through her Clash of Kings event chain, then all those king/region titles fall under your control automatically. Rhaesh Diaf, Rhaesh Has, and Lhazar are also very small regions (one or two duchies) when you consider the lord paramount mechanics and compare them to anything in Westeros (smallest has four). Perhaps: Astapor + Yunkai, Meereen + Rhaesh Diaf, and Lhazar + Rhaesh Has?
As an aside, opting to create the new free empire in Meereen as Daenerys doesn't change succession laws, which should probably be agnatic-cognatic primogenture, instead of agnatic gavelkind (since you usurped titles from republics).
As an aside, opting to create the new free empire in Meereen as Daenerys doesn't change succession laws, which should probably be agnatic-cognatic primogenture, instead of agnatic gavelkind (since you usurped titles from republics).