Personally I have been watching Yamiks videos since very shortly after I started playing the game. He had the humor the game laked, he taught me stuff, also stuff that might be considered in the grey area, but so did D2EA, and he is a much more well mannered creator than Yamiks is. I appreciate what both of them do.
Yes, it's fair to regard Yamiks as a core creator, with regards to ED, considering that he has 100K+ subsribers, equaling 1/5 of the regular players of the game, according to something I Heard Through the Grapevine