I listened to his video and ....
(1) He's made a great following with the accent. He mostly rambles but the accent is interesting to American ears (for a while at least).
Most players don't have 30+ years of experience and advanced degrees ... so ... sometimes one needs to repeat the simple stuff..
(2) He didn't say anything controversial, new or ... well ... particularly helpful.
In short, Figure out what you want to do it. Do it. Test it. Repeat. The harder parts of producing, distributing, branding, and maintaining are left for other videos. He finishes with go off and do it, you'll enjoy ... and now ... a word from our sponsors.
His advice was correct. Most gamers would tell you what is wrong. Few will note what is right (since likely that's just a repeat of the other systems they've played.) The first time you encounter real feedback in life can be difficult.
And, he even offered his 5,000 members as play testers if desired.
(3) He was not trying to discourage gamers from trying. Another 1,000 clones with a little different this or that hurts no one. Perhaps, one might be better.
(4) His linked stuff is standard fare. It's well made for the most part and expensive. Not crazy expensive but not cheap. Everyone on this site would pay a premium for something that was worth it to them. His products may not be that thing but maybe so. (If I was a battle map guy, I would look hard at his Kickstarter.)
(5) I say "his" but I sense there's a group of people with different skills producing the content. (One of his) skills is to ramble on camera.
(6) His advice isn't particularly helpful to an experienced Referee but that's not his audience. I find it comforting in a backwards sort of way that if this is that a "Great" GM is, somehow in life, I've managed to meet so many "Awesome" GMs. You know who you are ... so ... go out there sluggers and knock it out of the park.