I think your wrong about rexar. He's good in solo que, and solo HL. He just gets fucked sometimes by bad comps.... But that has nothing to do with the hero. Edit: I should say that bad comps can screw over any hero.
Also, even though chogall needs two people, I think he's borderline broken as fuck in QM and HL with unorganized teams involved.
Also also, I think the long list of solo que non-viable heroes would be okay if the game didn't have a bunch of generically good all the time heroes to begin with like ETC, Rehgar, falstad to name a few.
Like those QM matches you get sometimes when it's nova, li Ming, aba, chromie, artanis vs. nova, li ming, tracer, Sonya, gazlowe. Like, a shit show, but not a totally unbalanced shit show. And often still lots of fun.
The problem is when one side gets ETC and the other side gets rexar. But I guess that's the point, I just think that it's probably better in the long run that they keep adding more situational heroes instead of more ETCs. But in the short term it really makes the game unfun to play for me.
Edit again: What if power slide was just a displacement and not a stun?