I was part of Flash Runtime, not specifically Flash Lite. They were another team, as were AIR and Flex (and Flash Authoring though they were mostly one in the same way back when). Once Flash started to attack mobile, Runtime and Lite basically became the same thing, though Lite still had its own dedicated presence on feature phones. Flash on smart phones as a full-fledged, desktop-like Flash, not a “lite” version seen with older, less powerful devices. It wasn’t long after that there was the “FLAIR” merge too, bringing AIR back into mainline Runtime. It had been a branch off of runtime when it started but as it grew and became more beastly, bringing updates back in from Runtime became more and more difficult. Someone made the decision to bring AIR back into mainline and we all suffered horrendously for it (though it was probably the right call).
The team I worked with on the renderer was trying to get smart phones an upper hand in rendering flash content with the full runtime - something which could potentially spill over to desktop too, though mobile was our primary target. The core idea was use the GPU more, taking what Flash does now and offloading more to GPU rather than the CPU. There were a number of different approaches all of which worked great for a specialized application, but none performed well enough across the board, especially when trying to maintain an acceptable level of quality. I don’t even remember if anything we did went into the player in the end. It’s possible we found some shortcuts here or there, but there was no great revelation that allowed us to replace the renderer with something new.
I kind of jokingly say too soon because I honestly can’t recall half of it, or know what I might not be allowed to say. At the time you really couldn’t talk about much of anything that was being worked on and not yet released.
As for what’s happening now with Animate CC and what that means for ActionScript, I don’t know. I’ve been out of that loop for a while. If there’s not any conversion tooling for script in Flash/Animate now (AS -> JS), I wouldn’t expect them to add any. I’m actually surprised they’re keeping it around. The codebase is a bit of a mess. Well, it was. They did a lot of work during decarb (this is when they dropped AS2) cleaning it up which should have helped it out significantly. In fact I remember them working on that and some of the early, largely functioning builds would launch so fast you’d barely notice there was a splash screen at all. I found that pretty exciting.