Yes the moment you can pick pros to be randomly matched with is the moment everyone cries when they get matched with bads instead. And if it know you are bad and lets you not pick to be grouped with pros there will be even more crying. It devalues it as it will get nerfed. The people who refuse to use lfg sites will still refuse to use lfg sites. The stats will show that people can't complete it 90% of the time and it will be nerfed. The people who don't use mm will be the 8% that use premades. The other 2% will be tge actual ones to complete the content unless of course the content is mind numbingly easy. I know how all this works because I have seen this stuff happen before. PoE actually uses the best method of giving the easy difficulty mm and the harder ones not mm. Destiny just needs an in-game lfg, so you don't need to use 3rd party sources.