But then Alexis came out with something brutally honest, he has no idea to be a better GM. This is a good start. Often Alexis has railed about people not "getting it", and often this is when people are trying to help him (or at least in my case) be a better GM by looking at the problem with a proper critical mindset.
In this case, deciding what is a "better" GM. That is the most important step and the hardest for people to do. This sounds easy, but let me explain.
The first thing you have to do is decide what your goal is. Often people jump in "To ensure people have fun!", Stuart has famously pointed out the illogical nature of that question. The point of games is usually fun. That isn't quite it though (at least from my point of view). The problem I have with that viewpoint is that people don't truly accept that as their goal. They draw an artificial line and say "The point is to have fun, while playing an RPG in the following manner". That doesn't work, if the goal is "to have fun" take the basic consideration of playing an RPG out of this. Would you and your group have more fun playing Super Smash Brothers? If so play that. Fun is pretty vague and encompasses a large area.
I started with a different objective when working on Neoclassical Geek Revival. My goal was "Keep 4-6 people actively thinking for an entire evening with as little downtime as possible". I now had a goal and could objectively become better at being a GM. I have not found a better method to do this than an RPG, so then I started customizing the RPG to meet those needs. Each change is weighed against "does this keep people actively thinking for a longer period of the game". I will often go through several sub-questions that lead me back to this statement: "Does this reduce downtimes between players", "does this let everyone participate in the encounter", "does this encourage creative thinking", or "does this encourage decisions over problems".
Am I a great GM? Probably not. But now with each tip I read, and each thought I have, I can now see if I am becoming a better or worse GM and why. A consistent problem I see in rules development or GM techniques is failure to ask "Why?", and then when getting an answer to ask "Why?" again until you get back to your goal. If you can't get back to your goal by asking "Why?" like a precocious toddler then you are not becoming a better GM.
Do you have a goal with GMing? If so, post it below and then periodically look back at the game you just ran and start weighing your actions against that goal.