If I understood the Tribble thread comments on this correctly, the CE is not gone entirely, it's still available via the Private Queue.
Since it is pretty much unpuggable, that may make sense.
I think the CE could become puggable by one (seemingly, technically may be different) simple change: Don't allow it to heal itself back above each phase status. E.g. When you got it to 66 %, it can't heal beyond 66 %. When you got it ot 33 %, it can't go back over 33 %. This may give even Pugs a window where they can "spike" it to death despite all the healing fragments.
Even with a healing cap based on phases most pugs would eventually get stuck in the third phase.
First and Second phases are "workable" most pugs can realistically get down to the third phase.
The largest issue is the third phase with its "super shards" as I like to call them. This part actually needs pretty sizable teamwork to pull off unless everyone uses BO3 at once and they all crit or something do 9001 damage to it.
There is a multitude of ways they could make it work I'm sure. I just hope they figure out something, I'd love to complete it and get a trophy for my ship. And for the sheer fact of even simply completing it.