[foul]

I see only the 4th point as a real problem, which could be solved by fragmenting the network more, like connecting a server to it and not connecting the user directly (UI must reduce the visual noise of netsplits that should be a lot more frequent this way).

The other 3 are UX matters, 2nd point cracks me up because hexchat could split a message in batches of privmsg's eleven years ago, spam control is totally local (so being banned for spamming isn't a given), servers can nowadays buffer a lot of text and throttle messages, albeit bandwidth is mostly free.

Being them UX matters, they aren't worth much, thus IRC will remain broken because there are like two thousands IM competing software that dealt marvellously with those problems.