I wouldn't be opposed to this. Also, I think people do it for mmr dropping
You don't lose mmr from leaving skirmish arenas. People mainly use it to reset their cds. I've seen few individuals exploit it fully. Seen a rogue open with killing spree while queued with few alts, only to vanish and accept skirmish queue and repeat that whole thing few times. Any kind of deserter on leaving skirmish arena would be nice.
Agreed. Deserter for leavers. You join an activity to participate in, not to exploit it. Leaving shouldn't be done lightly. Legit IRL issues causing a leave outweighs a short term deserter buff from a skirmish.