doctorbadwolf
Heretic of The Seventh Circle
Let's pretend that DDAL concerns aren't driving design choices, shall we? We'll all be much happier designers...
Were it me, there would be no such thing as a ranged sneak attack except in very specific circumstances e.g. a stationary and completely unaware target such as a bored guard standing by a door. Otherwise, sneak attack could only be done via melee, returning to the idea of the 1e backstrike.
And the caster would lose Dex benefits to AC.
The "range greater than Touch" bit is irrelevant - it's casting a spell under duress at all that should provoke the attack - or preferably, in my view, just automatically fail.
Casters and non casters are pretty balanced in combat in 5e. Such changes would make casters pretty bad compared to a straightforward damage dealer with weapons.
Why is it even desirable? Tradition?