Yep, I made some of these comments. It would not cost Apple very much to enhance .mac especially at the enhanced cost/benefit ratio it would give Apple as more prople would sign up.
Examples are plenty, like an integrated web editable calendar, notes, easier calendar sharing, server side spam filter, push email, integration of .mac services into OS X like iCards in mail, more sync options, etc. or even a VOIP service with iChat.
It's really not hard to improve upon .mac and it is definitely not all about the iDisk space.
Well, bring it on. I have been waiting for years to see significant change, only to see free services pass us by. I tell myself that I keep renewing .Mac because I like having my @mac.com email address and dont want to change all of the things I have hosted there but I know that it is mostly out of some sense of loyalty. I mean if a fanboy like me isn't buying it who is?
Also, doesn't Google already have some form of all of those improvements you suggest that could simply be made to integrate with the iApps?