AA used to have mandatory forced upgrade as soon as a tiny handful of people junior to you upgraded. I'm pretty sure you went to the junior jet, not necessarily the one you were one.

I've upgraded onto a type I've never flown, certainly a sporting evolution but not a catastrophe for a motivated professional pilot.

I do see the issue with low time all around and perfect storm, so hopefully OO really keeps the screws tight on the standards. They're probably in a position where they can sacrifice a few slacker FO's in the interest of generating badly-needed CA's.

In the grand scheme the CRJ is a pretty easy plane to learn and fly, if higher workload on vertical managment (I never flew the ERJ, but mainline types work the same way).

I guess if OO wanted to be a little extra careful, they could limit the invol upgrades to own type. Or give you the option at least. That would make sense.