I used to like Game theory, but now I just find it annoying. My biggest problem is that I feel MatPat is making the majority of his videos just to promote something and/or get a sponsor for an episode.
And I am going to get this out of the way now: I freaking hate Deadlock. That Dark Souls episode was awful. Dark Souls is not terrible just because the life ring description has a freaking typo. And I hear the TF2 Vs. Overwatch episode didn't fair well at all.
Getting back on point: I liked Film theory at first, but it fell into the same issue as game theory for me: Making videos to promote stuff.
I don't mind YouTubers getting sponsors or doing promotions, but when they become common; I become irratated. It may not be as common as I think, but it's common enough for me to remember to bring it up.