Removal of Melee Upgrade.
After some rather discrete discussion over few years. Here's the reasons that we decided to remove Melee Upgrade.
1: The skill is either OP or useless, does not really serve as a proper "general skill".
2: When it's actually useful, it one shots people and the skill has virtually no indication and/or interaction with the victim. Basically, from the victim's view, a guy can come by you and just pop you instantly, and he can do that again well within one second.
It is not considered as a good design.
"Why don't we just add a cooldown?" Let's be real, why would you pick Melee Upgrade? If you are a new player, you have no idea what it is, and you most likely won't do anything at all with it, effectively wasting a skill slot.
If you are an experienced player, you use it to wipe out multiple enemies in a small space instantly, if there's a cooldown, the skill would be rendered useless.