Well as I have said in our Discord conversations, I think before any change is even fully fleshed out and suggested, the idea of what is "inherent" to the Scrapper AT (or, really, all of them) should be hashed out.
To me, Scrappers don't need/shouldn't have taunt effects, at all, in any power. Aggro control is not their job, killing shit expeditiously and without any support is. If you're concerned about mob saturation for Invincibility/RttC, I'd like to see survivability numbers that would support that. When I build for those powers, I set them to 1 mob in range, tops. Always hope for the best but plan for the worst, right? If you really want that 10+ target goodness, or you wanna measure your epeen by tanking Hami (which I did last night on my /SR brute, and my epeen was peacocking this morning, you betcha), play a Tanker or Brute.
Scrappers (should) trade aggro management and superior survivability for WAY higher base damage and Critical Hits. Full stop. Taunt doesn't affect your pylon time, or your AV soloing, the only thing people seem to care about is chasing runners...which is a bullshit lazy excuse when the "w" and "f" keys exist.
I fully support stripping all taunt effects from scrapper powers, and hey, if you want Brawl to crit? Fuck it, let's make Brawl crit. Standardization of things like that both help FOMO and stop AT-hybrid-creep, which I abhor. Blasters should blast, Tankers should tank, Scrappers should be able to go off-leash and do their damndest to solo the +4/8 spawns on their own irrespective of any other variable.