I work with kids, so they are always disappointed when the newer mobs, blocks, weapons, etc. are not available. So just having these objects would make it much more appealing. Stability only appeals to adults.
The most requested feature in my classes is creating new blocks or mobs. I know there was a client side modding initiative that never fully got launched. It would be great to see that come back.
Apart from that, kids always want to modify weapons too, so more features related to that would be great.
But really, I was asking in general because once a project doesn't have new development, it usually is not a good sign for its future.
I've been testing out the Bedrock MakeCode implementation, and it's fairly limited particularly in how much info you can get back from events. LearnToMod has always had the flavor of the "real thing", which is why we built our classes around it.