In busy airspace would ATC be able to respond quickly enough to multiple potential conflicts generated by an aircraft descending without clearance at very high rate through many levels? Perhaps this scenario has never arisen, but presumably aviation regulators will have considered the possibility. If so, what would their recommendations be for the conflicting requirements of rapid descent versus collision avoidance?
I think dream on about 'regulators' getting involved. The manufacturers write the procedure. Why does Boeing insist upon 10,000' level off? Because their TA is 18,000'. In EU that is still above TA and everyone is on STD. But I was told, in an RST, that I was wrong to go to FL 80.
If you lose separation with traffic within a few thousand feet then realistically there's nothing we could have done as by the time we get the avoiding action out of our mouth you have probably already descended through their level.
Which is why, IMHO, TA Only ASAP is more important than 7700.