I do like the sound of things like this, but my main concern is with how they're done, and the lag they can create. I've tried coding the same thing myself at least 3 or 4 times over the past few years, and no matter how I did it it didn't feel quite... right, if you get what I mean. There's been lots of ideas I've had which would need things like this, but right now the methods I've tried all push the game's features to its limits, and it looks like this plugin does it in the same way as one of my scrapped ideas.
I'm not against adding something along these lines, but right now I don't think the game is *quite* capable of it, although it's close. I worry about the long-term stability of things like this in the future, and updates being blocked because of changes.
It has been on my list for many years though. Don't take this as me shooting down the idea