So we need to update to this version anyway if we want any of drod's future work? That makes me sad...
What? Why? Why would a dev continue developing ROMs for an outdated version? The OTA brings people to .340, so everyone should get up to .340 in order to get the latest and most up-to-date ROMs. You have a few options on how to get there, but there's no reason to stay on 2.3.15 except for having a full sbf which, I believe, will be resolved soon, and may in fact already be resolved with that .320 full sbf.
So, when 2.3.9 came out, ROMs were created based on that version. Then 2.3.13, and 2.3.15. ROMs were updated for those versions. ROMs that were designed for 2.3.15 would install over someone's 2.3.9, etc. Everyone was happy.
However, Moto.. in their infinite wisdom made changes with the 2.3.3xx versions, that makes them not play well AT ALL with previous versions. So now, you can't create a ROM for 2.3.340, and have it "just work" with people on the 2.3.15 version.
Now ROM devs have to create new versions of each ROM they put out. Drod having three or four different ROMs he's working on (Blurry, Fuzzy, Focused, DX_Fission(?))... would have to keep up with 6-8 different releases.
I can't speak for drod on this... but from what I know-
--A good portion of his testers are now on 2.3.340.
--If he dev's for 2.3.340, then it's possible it could be backported to 2.3.15, but it would be very unlikely that it would be supported. (If it's broken, upgrade).
...
So to answer the question:
"So we need to update to this version anyway if we want any of drod's future work?"
Probably not. If drod doesn't make it available for 2.3.15, I could probably throw together a backport.. but I'm sure he will if there's enough interest in it... BUT, I wouldn't expect it to be tested or supported like the 2.3.3xx versions will be. (??).