You actually make a very good point, I didn't think of that. If BW changed the weekly from 9 wins to like 20 games played or something, that'd cut down on the rage quitting by far and wouldn't even need a deserter debuff implemented
Remember when Ilum was a mess but still had quests, and they gave you an alternative way to complete it? There were 4 quests. A daily and a weekly where you had to win so many, and a daily and a weekly where just completing a warzone gave you rewards. But the completion goals were very high (weekly was like 120 points at 3 points per warzone), so you had to do quite a few warzones, and that meant leaving was counterproductive. The only drawback is that defender medals were harder to come by, so the solo guard sometimes got a raw deal.
At any rate, a lot of players feel like this was the best setup for the reward system. Why they took the participation quests away I will never know.
Until I am given the option of excluding certain maps from my PvP queue, I will fully use my right to quit out of the maps I detest.
The thing is, almost nobody minds this kind of quitting. If you take the warzone pop right away and leave immediately if you don't like the map, the team is almost certainly going to get a replacement.