I was usually melee player (ret, rogue, fwarr) and i wanted to give something else a try, so i made hunter on this new season of frostmourne. Few days of playing and i realised there's like lag input when u try to spam skills... I was googling around and i found out about a term called " Spell queue window ". It started being very frustrating since i miss globals with this. Its not my internet, its not latency (usually goes from 30,40ms in game). Is there any way of fixing this via console commands or macros, or something else ?
In many many maaaaaaaany years of WoW, i have yet to encounter what you just described. I don't think this is part of the game per se, maybe some addon is causing it?
Nope, it's to make game more pleasant for users with insanely high latency. Are you using Quartz maybe? You'll see the ideal window in your cast bar marked as the red section at the end of your cast, when cast gets into the red it's safe to release the button and next cast will start instantly after the current one.
As for instant cast spells (like my beloved resto druid) it's just a matter of getting used to it I guess, here's a bit info about the queue for those unaware.
Check the section titled "Networking improvements" over at : https://www.warmane.com/devlog
It demonstrates how it used to work vs how it works now.