If it hurts endgame I don't know, but selling runs does increase rmt most of us hate so much.

I am by no means a good player, most of my FC out dps me easily, still I finished turn 5 with my old FC, with the help of voice chat. We actually got it in 2 tries...
That even surprised my old FC, and I believe I didn't even die at second run. Just listen very closely...
I must say my concentration that day was great, and I had really good voice guides.

I usually do longer to learn things, knowing what to do and my hands actually executing as I want is a big difference for me. It is just practice till it is all in my memory.

But everything is doable, only some of us need more practice. We don't need sell runs, I hope they ban it.

If people don't want to put effort in learning then they don't deserve the win/loot.
Yes finding a group that learns at the same speed as you is hard to find. But good attitude and patience will make the group pass one day.