benkei, the whole thing needs a lot of thought of course. that's why I am happy I am not dev, I don't feel like I could decide this, I neither want to.
It could also be damage, if damage points can be displayed instead of kills. But how much dmg would have to be dealt? A kill is easier to count.. well, maybe it's possible to count how much dmg was dealt to the enemy and take that amount.
Btw blindly charging in and trying to get the kill wouldnt help while getting a tk. A tk would, as suggested, give you -0,2mp. A kill only +0,1mp. If you get a kill and cause a tk at the same time, that would mean -0,1mp. And even 2 kills and 1tk wouldn't give the player any benefit.
Maybe the devs consider an idea like this. It doesnt have to be this actual idea. They already said before (I believe) that they think about changing the xp system, maybe smth like this helps.