Tell me how.
This is really hard (I will say impossible) to abuse, this is why this is here and not on suggestions
Its simple. If there is a way to abuse something then someone will find a way to abuse it. And this is super simple to abuse. Just report every player that kills you in a game of eggwars or a different game and just keep doing that. In my opinion this can do more harm than help because most people will just use /report and not report on the forums and since a lot of players would be using this command ir would be too much work for all the staff members. Let me list your suggestions:
-A fancy gui
Purely cosmetic it wont prevent people from abusing the command.
-a cooldown.
If all players use this, then that wont prevent abuse
-a database.
Just saves reports no anti-abuse feature
-preventing one person from being reported multiple times
It prevents some abuse but still reporting a player once that isnt hacking already is annoying enough for staff.
The only way we could fix most abuse is to basically add a pretty high cooldown and when a person gets reported a second time his reports are counted so staff can teleport to more often reported people.