In ST3, you can probably use this event:
on_text_command(view, command_name, args) (new_command_name, new_args)
Buwahahaha! This is so brutally effective it's not even funny.
It looks like it also allows me to block mouse events, which I've been wanting to do for the typewriter scrolling mode since 2011.
Thank you @bizoo for pointing this out. I am totally grinning like an idiot right now.
Indeed, I've been using