Your video was an interesting watch. Some of your tactics and ideas are sound but some I do question. I do like the idea of a more centralized flag and been at times placing it there. You are right in saying that it makes it tougher for opponent to get to the flag vs if you put it in the corner (too predictable) or behind the outer lake squares.
Your idea of miners behind bombs I find interesting, but also if you place many or all of them behind the bombs guarding your bombs vs their miners, you won't have any to get at their bombs or use to bluff a higher piece so you can get to that area you believe may have a bomb.
The idea you have of placing a Marshal up front to charge right away, I do question. I've faced many players who opt to do what I call "Marshal Blitz" they back it up with several scouts and a Colonel and charge on one side. I understand your central idea of closing off one section of the board, but I feel you give away too much information from the get go. What stops me if I have a well placed General on the other side to start counter attacking? If our General meet, then I have no fear with my Colonels. Many players also opt to bomb out one side of the board, what if your Marshal is on the wrong side of the board? You already gave away your plans and now you have to spend extra time to either reorganize your army to get your Marshal back into the game or hope your one miner up front can break through his bomb area.
One other thing I do question with the setup is: you have very few front line pieces that are backed. The ones that are, they have a far gap apart such as your Lt. up front being backed by the General. I feel you give away again too much information using your General to take out a Captain when you could have a Major on the 2nd row below that Lt. You have a Sergeant leading a charge behind a Lt. on your left flank and it only takes one Captain from your opponent to clear out your front line and many players do lead charges with Captains.
However, I did like your bomb structure on the left and backing that Captain with a Spy, it is different and pending if you discover your opponents Marshal early on, you can get your General backed by that Spy within a few moves if need be.
I do suggest that you make modifications to your setups from game to game, because the last thing you want to do is become predictable and people figure you out. I'm sure the Great Sun Tzu who wrote the Art of War probably has some passage talking about not changing up your attacks. Overall, this setup is good vs weaker to average players, but against the more experienced players you may need to change up your plan a bit.
Anyway, I do appreciate the time you took to make this video and wish you luck. I have another name of mine that I once got to 18-0 and I agree with you it can be tough with the random players you can face at any level. My name here I play a lot of friendly social games (unrated games count towards wins/losses), play with mixed up rules, or have to talk to members since I am a moderator on this name. As you will see I'm only in the mid 50% on this name but, my other names are higher.