I'm not a super-pro uber skilled player just to clarify.
I like the competition, but I play for fun.
The fact that ragequitters are legion in the game should not change at any price the gold that you earn when you do a kill or other variables linked to the game.
It's more like a "social" problem. Look at DotA, they have the same problem and they more or less regulated that with some additionnal features like banlist, listchecker & co without even thinking about removing some features or nerf some things in the game to counter that.
If a player got frustated because he found someone better than him shouldn't be an excuse to leave a game. I got owned numerous times in numerous different games, I prolly never leaved for that. I fight untill the end, say GG and then try to understand why he/they played better than me after the game and try to rectify what I did wrong in the next game.
I prefer to add a system that permits to regroup players from the same level in order that they can have fun between equally skilled players and maybe in this way, it will be a little be less ragequits (others ideas are welcome, that's just one of them)
Even if you invest in items that give armor or life, it will never compensate your teamplay/moves errors and you will always die at the end if you're not playing "well".
that's my vision of the matter.
Edit: Thanks meta to help me to express what I think. It's not really easy when you have a poor vocabulary like mine 