I love your blogging about issues I haven't really considered, but are actually quite important. On top of informative, it forces me to stop and think, which is a good thing.
Like with your last entry (about quote marks), I have to point out that most VNs use the character encoding cp932. ‽ isn't included in that one, meaning while we might see it in the wild, it will not be inside VNs, at least not those using Japanese engines. It might appear in engines using utf-8 (those claiming international support). Doesn't look like solving !? or ?! with just a merge to ‽.