I was at a Cognos 11 session hosted by my local Cognos user group and the IBM reps mentioned that support for portal pages was being actively looked at for future feature releases. Having reliance on lots of portal pages is one of the few use cases they advise waiting to migrate. As for 'shortcuts', there will be a REST api document coming out in future and I expect that that will provide more robust linking capability. This is not "official from vendor", just what we were told.
hopefully this is helpful.