[JamOfBoy]

I don't think it's meant to be more than a tool to get to someone's rear. It sure does sound boring, doesn't it? Just moving behind someone?

But think for a moment about the context of Rough Tumble. You're a Rogue.
You're probably using a dagger. You've probably got Thorn Scratch and Flank. If you're a VA, you've probably got Cutthroat and Backstab. If you have a dagger, you're building GUI, meaning you've probably got a high Flanking hit bonus.

Lets assume everything above is true. You use Rough Tumble, costing 1 momentum, to get +20 Evade, go Airborne, deal around 12 damage and get a Flanking hit bonus of around 20-30 Hit assuming you land directly behind and there are no allies adjacent to your target. You gain a total of 26 effective additional SWA and +10 Crit through Flank and Backstab when you use Cutthroat to inflict Silence and Knockdown.

This is not counting any pre-applied buffs such as Southern Wind, Northern Wind, Veil Off, so on so forth.

Admittedly, these are optimal circumstances. Not every Rogue is a VA, not every VA uses a dagger, etc etc yeah yeah I get it.
Rough Tumble is already loaded with potential, it doesn't need to be a defensive tool - no evade buffs please.

Edit: You either pulled these numbers from Embroidered Windswept Gi, or they're just coincidentally the same. I don't think a 1m skill should be comparable to a difficult-to-obtain torso slot item.