Agree about DCC but lot of the other issues you list are due to curmudgeonly (IMHO) users insisting on using non-modern clients and networks.
If they would tolerate a little breakage of backwards compatibility, the big networks could easily move to utf8 with standardized identity and colours, etc.
Unfortunately there is a small but very vocal faction of IRC users that are highly entrenched and resistant to change.
At the same time, that existing base of legacy IRC clients and servers is the only reason it could be worth hanging on to the old protocol. If we're going to break backward compatibility, we might as well take the opportunity to fix all of the other long-standing issues with the protocol.
I still have hope for the IRCv3 project, it appears to be fixing a lot of the issues mentioned. I'm on Matrix, but until #debian moves, I'll be found on Freenode and OFTC.
If they would tolerate a little breakage of backwards compatibility, the big networks could easily move to utf8 with standardized identity and colours, etc.
Unfortunately there is a small but very vocal faction of IRC users that are highly entrenched and resistant to change.