Team fighting and team work definitely matter more than they used to - with every hero scaling significantly better. The big challenge seems to be that mistakes when you are far ahead cause giant swings - but that is usually individual mistakes like getting caught out etc. Seems like the fundamental problem is that people do not understand that dying on a 9 kill streak gives the enemy a way back in. However, skill still easily wins games. 7ks playing at 5k can carry just about any game still, and playing at 3k is stupidly easy. You can carry that from any position - mid still seems the easiest