Maybe they simply… won’t!
Besides these technical difficulties (that could be solved by automatically adjusting the bubble-size to the displayed text by the game-engine - maybe it actually does that for the japanese text already), if the scenario that Narg painted would come true, we could say bye-bye to every new localization anyway:
If the japanese government really would wants to ban all exports of erogames from Japan, they certainly won’t leave out the loophole of letting those games, whose export would be then forbidden, being localized by an inside company and then being sold by a cooperating company outside of Japan. After all, the localized game would still originate from an originally japanese erogame - and the fact that it would even contain demosaiced ero-CGs that would be borderline illegal under japanese jurisdiction should make things even worse!