They do maintain the simplicity of the line oriented protocol, so I'm fine with that. :)
That's the strongest point of IRC, IMO, and why it's kept so simple : every instruction is a plain text line, period. It makes it incredibly simple to build on top of it. You don't need to introduce a dependency to a project that probably will be abandonned in a few years, at which point you'll have to rewrite your codebase to use an other dependency, for a few years. You just open a TCP connection, you read lines from the socket and write lines to it, each line is its own instruction structured in well known fields, and that's it. It's so simple!
As long as IRCv3 sticks to that, they have my blessing. :)
Yep, as often, the extension of the standard comes from non standard features developed here are there (as you can see in the participating organizations block, most of the big names are working on this). The difference in ircv3 is that you can expect to see all those features everywhere, instead of having this software implementing this feature, that other one having that other feature, and you have to choose which one is the most important for you. Basically, it's a rebase of the standard. :)