It won't change anything, I can actually see it making things worse tbh.
Well your gonna have a bunch of people who have played for months starting from scratch on true skill. Considering the player base is also much smaller now also....
Its going to be really bad for probably around 2 months if not more before it can really sort out peoples real trueskill.
For the limited number of people that actually have thumbs, search times will be increased if the mm will actually go out of its way to match by skill. Most of the halo community is awful so I guess it really won't effect most.