Powerslide headshots also count as crouching and will trigger Flawless Execution, slugthrowing shotguns work well for this like Chaperone or Retold Tale. Otherwise I recommend actually just crouching with a longer range weapon, potentially with Knucklehead to retain radar, then while FE is enabled, close distance to target, and as OP said, then activate SB and go for the kill. Also, You are not entirely invisible on the Motion Tracker. You WILL ping, however the interval is much longer between them, which should allow you to close the gap. However, on top of this, you aren't truly visually invisible either, you have a smokey purple outline which to a trained eye is actually easy to see. I've tested all this in private matches as I've done all the new supers so I make sure I understand how they work. But yes, a shotgun will one shot you, and with the crap hit registration you won't even trade. And forget about dueling super vs. super with any of the other roaming supers, their damage reduction is too high to justify taking them on. (This also sadly results in a lot of panic supers which give them a huge spike in damage reduction and they immediately murder you. *stares at Fist of Havoc*). There are advantages, despite the fact that people can still somewhat see you, if you actually open with a heavy attack, it will OHK a guardian without their super active. Additionally, you'll immediately turn invisible after the kill. The light attack is the one that has the crap hit detection, but since the heavy is a vertical arc, it has a higher chance of actually hitting. Just my observations as well ^^