Yes, I desperately want this. I took some time off and played other games with hold to cast on skills that are spammed and it's such a good quality of life upgrade. Playing Caster in PvE/PvP is just asking for Carpal Tunnel at the moment.
No thanks. What would be nice is if global cool down was reduced though. Most of the time its not lag that holds me up its global cool down preventing me from casting for .01 secs so I'm already moving on in my rotation. Yes it can be worked around. Yes we need some sort of global cool down. Currently though if I swap from a normal to a mechanical keyboard its extraordinarily noticeable. This is the only game I play that I must hit the key 1-3 times and still cannot trust that my spells will fire on time. Lag does compound this issue. It really sucks in an open world pvp game to not be able to trust that your spells will always fire. Gotta be real careful on timing stuff.
OIC about global CD. I just want something that can be toggled on and off at your whim. I don't feel like spamming Q in pve after working for 10 hour. I could care less about losing gear when I am faming. I would turn it off when I'm playing specifically for PvP like you have pointed out.