True, and I also don't see it as something needed to add.
The main advantage from firing multiple perks from one button is the lower requirements to both the multitasking abilities and the mechanical abilities on managing hotbar changing and pressing the corresponding buttons while paying attention to your surroundings and what enemies are doing.
Something experienced players have learned. So yeah, it may make pvp easier and the may even be one or a few occasions where it can improve on alpha reliability. I don't really see the need to make pvp easier and won't shed a tear if the queueing of perks isn't implemented. "New pvpers" may screw up less - but I don't think it'll change the gamebalance on expierenced pvpers that much.
I'm not quite sure I follow you on that. What difference does it make on acrobat, evasive stance or dodge the blame? They too also have execution times. Not quite sure what you mean by no dmg mitigation is possible.
edit:
I read what you wrote wrong. Yes I suppose that can be a valid concern that someone could fire off all 5 perks instead of.. say.. 1-3 perks because he queued them up faster. Didn't think of that.