I like the squad leader vibe as well. I mentioned in another thread (the extra attack one I think), about allowing Reliable Talent and Stroke to be used earlier but at a more limited rate. I think if you combine that, with the ability to share Reliable Talent (either to 1 other character, or the party for a group stealth check).

Something like level 2 or 3 can use Reliable Talent 1/Short. Level 6, 2/Short and can be shared with another party member or as part of a group check. Bring Slippery mind down to 7 or 9, and add a 1/Long use of Stroke of Luck at 15. Blindsense could be brought down to 5, and just add another ASI there. Mix that with some of the sneak debuffers from 5.5 and Rogue gets a solid buff while still keeping the same mechanical feel.