The play design group released an article on combo on the mothership: http://magic.wizards.com/en/articles/archive/play-design/philosophy-combo-2017-08-04 Main take away, we think it's good to have combo in Standard so long is it's no good. I also did a nice double take on the idea that combo should not be faster than aggro, given that the old saying was that aggro beats control, control beats combo and combo beats aggro (which of course has been an obsolete saying for a while now but still). But if it can't beat aggro, then what is combo supposed to beat? I guess I'm still stuck in my mind of a combo deck being a glass cannon with search and just a little disruption/protection. Seems that combo nowadays isn't an archetype so much as it is just a win condition, in order to see play it has to be compact enough to fit into another archetype shell.