I think the next GDR update is fairly imminent, it's only 6 months or so since release so not too bad and there's been a bunch of small updates in that time.
Out of interest, what is missing/holding WP8 back from your perspective? With the exception of a couple of apps missing I quite like it, granted it's not as "pretty" as some of the Android builds, I find it much easier and clearer to use practically day to day though once I got over my urge to "fiddle" with it as a hobby.
Purly on an OS front, some big things like.
Notification centre, its hard to get away form how helpful this is, and pinning EVERY tile that might get an update or message is not the answer, a nice implementation is swiping the other direction to reveal an centre with hot buttons to turn wifi on off etc and the like.
Alots could be done with the Mail client to make it work better with multiple accounts.
Different volume presets/ profiles for things and how about a constant vibration option, not just a single vibrate then....nothing. Custom notification sounds as well, its little, but I miss it.
Text/ message reminders if you didnt get them the first time, how can somethign this small and useful not be a standard feature?....I dont always hear the first ring of an SMS and found the 5min tone reminder catching me out to pick up the phone.
Ways or options to group your Apps list..favs at the top, random not so much used stuff in other groupings.
Two things that need to be binned and started again, Xbox Games centre is pretty awful, it needs to be redone from scratch.
And dont even start me on the Music player, its pretty awful overall.
I still like using WP, but theirs just so much more they could have moved on.