Recently i have seen many topics and posts talk about the alt-f4 from the queue which is in my perspective became more after the prefered map choice was introduced, so here is my suggestion and why.
I suggest to remove the prefered map choice completely from the system and back to the old pool queuing system and this will be much better, why? In the old map pool you have a choice to ban 3 maps (1v1) so you still have another 4 maps which means even if a player alt-f4 his chances to get what he want is waaaaay less because he has another 4 maps in the pool, so his chances to get his stupid a a specific map is only 25% unlike now, because now with the boring prefered map choice the alt-f4 is actually better because there is a big chance next time to have his prefered map unlike the old system which in that time he will accept the other 3 maps regardless the map he like because he choosed them right?! He banned 3 and have 4 good maps from his perspective which means he should accept playing those maps regardless which one he like the most.
So the bottom line is just that the devs should get back the old queuing system and delete the prefered map choice.