That new engine is indeed probably gonna be an issue, it may means that the way some things work in our Ages wouldn't work anymore and would make Uru crash. So we would have to change parts of our Ages.
But that may not be the biggest problem, Cyan has said that there will be changes in the Uru files, and most likely the plugin won't work at all anymore. And, at least for a time, we wouldn't be able to create Ages again. So, our programmer wizards would need some time to adapt it. Also, because Cyan will release their own tools they might ask us not to work on the plug-in anymore (if only for legal reasons).
About UAM. Whatver way Cyan choose to handle the custom Ages I'm pretty sure that doesn't involve UAM; as sad as it is. There are legal and strategic reasons for this. This is sad but I'd be really surprised if they go with it. Also, they already have everything they need technically to include custom Ages in Uru, they don't need UAM.
I've given this some thought lately and it seems pretty clear that most of what we do here these days: the Ages, the tools etc.. will go to waste at a point or another. That is pretty clear to me.
Does that mean we should give up? Certainly not. Because not all of what we do will go to waste; we may need some time to catch up on the new situation but we'll get there eventually. Also whatever Cyan has in mind this won't happen before several months, most likely not before october or so..
And finally I think we have to show Cyan our involvement in these custom Ages. The more work we can provide the more they will be motivated to support custom Ages in Uru Live.