Comment by xg15

Yeah, making a specific "Turkish lowercase dotted i" character which looks and behaves exactly like the regular i except for uppercasing feels like introducing even more unexpected situations (and also invites the next homograph attack)

I guess it's a general situation: If you have some data structure which works correctly for 99.99% of all cases, but there is one edge case that cannot be represented correctly, do you really want to throw out the whole data structure?