I remember the long debate about pets before they were added. One of the main issues was that no one wanted them to die, like they do in the offline game.
I believe that the running away/being removed was the work around to dying.
When the pets came out, they had no idea that the market for rares would develop like it did, or that we would ever have mega millions to 'pull' rares....it was meant to be a random lottery, where everyone bought unopened crates and sometimes got a rare. It was only later when roaches were added that cats chased mice, dogs could be trained to sit or attack or that the chance of mean pets were added, just to give more dimension and unpredictability to pets ownership.
That was quickly worked around to pet stores opening as many crates as their lots could hold....back when everyone was wanting a pet, they could still sell the non-rares easily, when the mean pets were added, store owners sold them back, because no one wanted to buy them. Then someone figured out how to 'pull' for rares, with the sell back, at a profit. And the rest you all know.
My point being, that the design was never set up to handle the trade in rares. No one 4 years ago, ever considered that we would be in the place we are today.
It has been said over and over, that the game cannot distinguish between a rare and non-rare pet....so if they remove 'mean' and 'running away', it would have to be for *all* pets...is that what we want? Is there a better way to give pets some variety, individuality and unpredictability? How could we redesign pets to make them more fun, and not just another greening or repair tool?
If we think about this and work it out, we might end up with a design for the Wiki, that they may be able to use, to change the design of pets in EA-Land.