New Steal: Level 1-30

It's range is so far and the mobs everyone trains on are so packed that such a thing really doesn't matter.

Steal on 3 targets should easily out damage SB. o.o

80x6 vs 130x3. You do the math.
Well, technically it's 80x6/0.96 vs 130x3/0.8 (assuming the new Steal still has the same speed), which ends up being 500 vs 487.5. SB still wins.

And no matter how packed the mobs are, it's always going to be easier to hit 1 with SB than to hit 4 with Steal.

On the flip side, maxing SB first renders Double Stab useless immediately, while maxing Steal first gives you something else to work with entirely. Double Stab isn't a bad 1v1 skill at all, especially considering its speed.