I just added this script to my game and I'm really liking it. It kept a consistent 40 FPS on a 500x500 map with 1000 events, half of which are moving around, while the FPS drops to around 5-9 without the script. Great work.
Integrating the script with my tactical battle system took some time because I was extending the map, character, and sprite classes in ways that the script didn't support. I rewrote my classes to inherit more of their functionality from the default classes, to delegate updating and drawing duty to your methods instead of my own extensions, and edited your script a bit to account for me using battlers instead of characters for graphics, and it seems to be working well so far. In a way, I think adding your script improved the structure of my own scripts (much less duplication), which is pretty neat. It also helped me find some bugs in scripts I haven't tested in a while.
I'll keep you updated in case I find any bugs with the script itself.