Yes, servers probably should return that info in raw 005 or similar, but nonetheless there will (and should) always be a limit as to how high that number can go. Whether that limit would still be 90 in that situation I don't know, but I'm sure there would still be one. For instance NICKLEN already exists for the length of nicknames, but if a server returns NICKLEN=260 I can say with reasonable certainty that mIRC won't accept that. Actually I haven't tested that theory at all, I'm way too lazy to setup a server to test it, but it would be surprising as hell to me if mIRC allowed it.
bloupx: It's not just a matter of taste though, it's a matter of practicality. It's not practical for mIRC with it's current line length limitations to support very large channel names and it's not practical for any user wanting to join that channel to do so.
