Can you fit everything into 32 bits? I have no idea, but Hangul and indict scripts seem like they might have a combinatoric explosion of infrequently used characters.
But they don't have that explosion if you only encode the combinatoric primitives those characters are made of and then use composing rules?
You still get the combinatoric explosion, but you have more bits to work with. Imagine if you could combine any 9 jamo into a single hangul syllable block. (The real combinatorics is more complicated, and I don't know if it's this bad.) Encoding just the 24 jamo and a a control character requires 25 codepoints. Giving each syllable block its own codepoint would require 24^9>2^32 codepoints.
Exactly ! That's what I understood after reading this great post https://tonsky.me/blog/unicode/
"Even in the widest encoding, UTF-32, [some grapheme] will still take three 4-byte units to encode. And it still needs to be treated as a single character. If the analogy helps, we can think of the Unicode itself (without any encodings) as being variable-length."
I tend to think it's the biggest design decision in Unicode (but maybe I just don't fully see the need and use-cases beyond emojis. Of course I read the section saying it's used in actual languages, but the few examples described could have been made with a dedicated 32 bits codepoint...)