I'm not sticking up for either party here, both seem to be a bit immature.

But I will say that I think everything would be fine and dandy if we could still queue up an ability in the middle of an unrelated ability.
Nobody would burst into fire if I didn't have to sit there and pray I got the timing perfect with a reaction style ability. Even competitive fighting games have a buffer, seems odd to remove it entirely from a latency prone MMORPG.