The drag is because it's an order. Sort by due date, and then if two items have the same date, sort by the next criteria..
I don't know of a way to sync it.. I won't say it definitively can't be done
Because it still does create a local calendar on the device, which other apps can read
So if there's another app which can sync a local calendar to a remote one, that should work (but most sync apps are the other way around -- syncing a remote calendar locally, which sounds like the same thing, but the difference is that they create a new local calendar that syncs, rather than an existing one)
Well I am using taskwarrior and thinking about switching to todo.txt. I actually wanted to have some script on my server which woul create events based on some keyword in my task list. At least this should be a bit easier with todo.txt.
Lua scripting is approximately 100% of the reason why I use Simpletask, and ST is maybe 80% of the reason I use todo.txt (the other 20% is being able to do something reasonable with the file in a plain text editor)