I can see how it sounds that way, but I assure you it isn't the reason.
Could you clarify on these game mechanics that aren't being used?
None about win the war, as there is only one way to do that. The mechanics I talk about are the depot and HQs. Some of these hordes could be split into two buff groups to climb to and level the Ammo and Troop depots. 30 minutes after those groups launch you launch 5-8 pairs of heavy fights/med buff to pork a full front line set of bases of both ammo and fuel. How long would the ammo and troops be down along that front? Even if the porked team got together to resupply it would take a while. You now have a "protected" front as they are either too busy resuppling, or have no ammo or troops. You now attack the other front line and grab a bunch of bases. Almost never used
Carpet bombing. You do know that some people have figured out the salvo and delay that is best to carpet bomb towns and white flag them in one pass. almost never used.
Well HiTech said he wanted to add submarines, with the new water I see that totally possible. Meaning the dams could be added as well, bridges - we have them now - but on land with no water.. just make them destructible
HITECH has said he'd like to add sub to the game.... because his father was a submariner. He has also said this for over 10 years. You talk like were getting it in the next update. How much do you know about the new water? To me it looked like it had depth, but that doesn't mean it does. In the video, how big were the "swells" we were seeing? No way to tell as we can't be sure if we were 2 feet of the water or 20 feet. Dams, bridges "just make them destructible", all of these things, your assuming a LOT, and very possibly reading in a lot more than what is there, planned, or possible.
I know what I'm asking for completely changes the core foundation of their system. I'm not asking them to abandon their core foundation (capture 20%), but I'm asking them to add on to it. So those who don't want change, don't have to embrace it, but those who want something different can have it too. In a way I'm a people pleaser (within reason), I try to make everyone happy, and when I see that something I said be it an idea in this case, that makes it too hard or is unnecessary, I try to compromise.
What I've asked for, would give purpose to otherwise meaningless things. Some of what I've asked for is already modeled in-game, but has no meaning, like the bridges. Why is a large airfield "worth" the same as a port or a V-base? Even if they changed it so you needed a certain % of enemy ports or specific type of bases, I think that would change it up a bit. So instead of steamrolling, you would have to actually plan. Say knights have a port that bishops need, but the knights took it from the rooks, and the rooks need this port so they are eligible to win the war. (Remember my keep # of your ports and take # of their ports in previous posts?) So, you have bishops going for this port, knights trying to defend it, and rooks trying to take it back! It makes that base actually worth something.
Whereas now, it's take any base that is in sight as long as we get this #. It lumps all the base values in the same pot, even though they are vastly different. I fully understand why they did it the way they did. Simplicity, Be it for their sake (time work etc) or for the player's, so they don't have to learn anything more in an already difficult game. These are merely suggestions for the New Terrain Engine, which will unlock new things for them to experiment with.

At one time HTC added a base capture order. Basically it was suppose to make it easier to find fight because the enemy had to capture bases along a certain line. Your "must need certain bases to win" smacks of the same idea. It was a horrible experiment and was soon removed.
There are many ways to play this game, however most play it only one way. Whether that is base capture, GVin, furballing, NOE hordes, in your face hordes, or only flying blue planes of CV's. Everyone get into that mode of play that they enjoy. Some of us fly different planes, do bomb runs, or jump in a GV now and then to change it up, but most stick to one thing. Adding extra stuff may be fun for a bit, but it wears off and they go back to that one thing they really enjoy
Changing game play isn't something that is done lightly as it effects HTC pocket. While to us this is all fun and games, to them it is how they make their living.