I used to play the free online FPS "Wolfteam" for a while. I eventually quit it because getting killed repeatedly by people who chose to just focus melee kills was rather frustrating. I mainly just used the wolf form to move around quickly, but there were some people with 80% melee kills. Sure, getting a wolf to drop before they manage to slash your face off was rewarding, but not enough to make up for the countless times I was slashed as I went around a corner.
Games that put too much focus on melee are more frustrating and less fun than ones that give it to you as a last ditch or situational tactic. SD decided to make Brink melees a tactical move instead of a damage focused one, and I'm interested about how it turns out. On paper, it sounds a lot more fun to me.
My only worry is that melee kills might effectively become a one hit kill, if it means you can just knock them down and spray them till they die without a chance to shoot back.