Yeah, that's one of the reasons I quit using the WoWI author portal. From an user standpoint, I felt like having tickets for 30 addons all in one place was a good way to discourage users from using the ticket tracker, especially looking for existing tickets about their issue. From an author standpoint, it's nice to be able to see all tickets for all my addons in one place, but not being able to filter them at all (even to hide closed tickets!) wasn't so good. I ended up just deleting tickets instead of marking them as fixed/added so they didn't clutter up the list.
Regarding sorting, you have to click "Long List" and then you can click the direction arrow on the "Date" column to sort backwards or forwards:
http://www.wowinterface.com/portal.p...so=desc&page=1
There's no way to filter that list by addon, though, so it may not be as useful as you'd think.