I've been seeing a lot of posts to this thread lately. I posted a while back and I'm still hoping Apple is working on some sort of solution. I'm guessing the way it integrates with iOS makes it more complicated since they need to provide a solution that synchs properly across iCloud and linked devices. Still... it blows, and I wish Apple would at least acknowledge the issue and provide some sort of feedback.
That said... I wanted to highlight an interim solution that 'e-bear' (perhaps others) have pointed out which some posters may have missed:
You can click the pop-up notification banner itself (instead of the 'Close' or 'Snooze' buttons). This will launch iCal or the Reminders app (depending which you used originally) and the related event/reminder. Here you can change the date/time to the next moment you'd like the alarm to sound/display.
Obvioulsy, a dropdown with options on the pop-up notification itself would be optimal, but this is better than hitting snooze every 15 minutes or closing the reminder all together.
I doubt we'll find a third party app (as some have suggested) that fills the void since the best solution would need to integrate with iCloud and synch with all devices.
Hope this helps keep the sanity until Apple gets back to us.