Extend kill assist timer

I cannot tell you how tilting it is to get an enemy to 30% health, be 10% yourself and be waiting for your jungler to kill him but it take more than 10 seconds to get there and kill him, so even though you made a free kill opportunity you suddenly don't get the assist. Or worse, when you duel with somebody, start to run toward your ally, and then they go to chase them... and it takes 10+ seconds and you don't get the assist. Ganking a lane, getting them to 30-50% health, and they stay in lane only to be killed by the laners when they come back and the jungler gets squat for spending his time to help his team instead of farming.

Maybe I'm just a scrub and a bronzie or whatever, but quite frankly I don't think 10 seconds is quite enough. At least extend it to 15 seconds, if not 20. More than twenty I think would be too much, but less than fifteen I think is too little.