There are 2 main issues with the Quick Chat.
First being that it's very barebones and recycles sound effects for multiple things, second being that it's spammable and the GMs are quite slow to react to the PvP reports (do they go to the taskforce instead of regular GMs?).
Fixing the first would take some effort but it would be beneficial in the long run. Cleanup useless options such as "Hello" and add unique visuals and sounds for the remaining, such as adding a small Job sticker of your Job over the enemy you use the "attacking X" on for a short while. Showing MP and LB as % number over your head quickly when you press the corresponding informative quick chat. And so on.
As for the second one, limiting the spammability of same command would help some, but the real solution would be to put a regional GM or two to prioritizes PvP reports so they could slap the people who abuse the system faster.