I jut ran Market Crash on my Super Reflexes/Staff tank. I was lvl 42, sidekicked to 49, and we ran with +1 level notoriety so we were fighting lvl 51 and 52 mobs.. I had no real effort at all until the end fight - I did have to mind the Super Stunners, but some other tanks have that issue too. In that fight, I died 4 times, while no-one else died in the entire run. We had a kinetic doing a reasonable amount of healing at random times. It is interesting to note that the times I was away, no-one else took severe damage.
Statistically, a SR tanker will be hit now and then, and once in a blue moon hit by a series of big attacks that can take them down. But the Crimson Prototype's attacks did so regularly. Anything that auto-hits is naturally the bane of Super-Reflexes, I don't know if the Crimson Prototype does that, but the extremely large doses of damage it does (about half my health) only requires it to be lucky twice in a row.
I was tracking my damage resistance, to see if the resistance bonus from the SR passives kicked in. I normally have 34% s/l. I think I saw it go up to 50 one time, but not more than that. Again, when damage comes in very large packages, the resistance from the passives don't seem to have time to kick in. (I am aware that the monitoring doesn't always work.)
I've suspected for a long time that SR would not cut it in the end game. It has solely defense and defense debuff resistance to survive on. No hit point bonus and no resistance. This is the first time I actually felt this was an issue. It would be interesting to see the results of datamining on how Super Reflexes on tanks is doing at different levels. My suspicion is that they don't really work after level 40 and barely at all in incarnate play.
If I am right, what can be done? If tanker SR is to be boosted, I think its the passives that should get love. Increasing the amount of resistance they give, and have them give it earlier (at lower levels of damage), possibly starting at a moderate resistance even at 0% damage. I could also see them give a buff to maximum hit points - almost ever tank primary has that.