Is it possible, with only three sides, to have the homogeneity you seem to seek? I can't see how it is possible. You aren't the only one to express this thought, but I just don't know how realistic an expectation it is.
The MA, or even to some extent an HA, just isn't structured enough to have that "oneness" of mind. Scenarios work because you can boot a guy's butt if he doesn't play ball. Here, they tell you what you can do with your war.
I have expressed my opinion enough on the war concept (fine if you want it, fine if you don't), but short of that I'm not sure what you are calling for.
Defending a nation? At times that is incredibly hard to do. You have both opposing sides burning the candle at both ends, you are undermanned, and they have shut you to two fields. You can fight, but most usually it is in vain. Then you hear the geniuses telling everyone what they did wrong, if only they had listened, people start yelling at each other... reminds me of one of those plane crash scenes in the movies where everyone is up in the isle screaming and waving their hands around.
In concept, I suppose it would be nice if people cooperated more, I am all for that. The core problem with that thought is, if you have a whole country coordination you must have an all-country leader. God forbid it. Got only two words for that- "Bus-Boy".
I don't want to flog a dead horse, but here is an example of a good night... I log in, find a base that is in trouble. I get to hop up 3, maybe 4 times. I fight a few, die a couple maybe, then it is time for me to be out. I may help save the base, it may be lost. Then starts the "why are you wasting time over there you idiots!" type comments. I'm telling you, if we had an A-bomb, and I by some miracle had enough points to acquire one, ground zero would be our resource area. (Not really, but I sure do enjoy the image of THAT text buffer!

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In the end we don't seem to be able to exist in the same world peacefully, but I don't know what the answer is. People who take the strat seriously look at furballers as time wasters, wasted resources and effort, and let that detract from their own fun. Furballers don't want to get entangled in a war in which they have no interest. The only thing a furballer hates is not having an open field.
As to the country nationalism is concerned, I wouldn't agree with extending that too far. I think it is ridiculous to hear people made a pariah because they switched countries. Big deal. I've always been a player that will switch to a low side if they are overwhelmed, sometimes right in the middle of the session. In the games I have played I find it is much more fun to have an opponent to fight than to find empty fields to rape. But oh, let someone do that, and you really hear it. I know, heard it plenty myself. I will never understand how it can be fun to take over bases that aren't even challenged, at least after the first ten times or so.
The most detestable act I have witnessed is the act of holding a country down to its barest minimum of fields and resources, and setting up vultch parties. I have tried to defend fields enough in this situation, never again. This feeds off the desire to defend one's country to the end, for some patriotism, and in the end you just pad some pilots scorecard. No, patriotism shouldn't extend to the point where you are exploited because of it. Making it an offense to switch sides only feeds this behavior. Just today someone posted they felt the need to log off because his team was being overrun, and they didn't have enough fields left to fly. That cannot be good for business.
My counter-question then would be, is it desirable to have opponents in war simulation, or is it better to pound the other side down into a defenseless position and hold them there? Is it better to have that occasional lone-wolf sortie where you find the perfect pilot that is a match for you, you have a 10-minute duel, and win or lose you had the time of your life, or find that same guy alone and you bounce him along with your four other buddies, each fighting for a piece?
What is really the issue is that many have the desire to play the game like chess, that is be in overall control of the group or country, and move players (pieces) to just the right place to counter every enemy move. Others just enjoy the chance meeting with a skilled opponent, fighting an epic one-on-one, judging his energy vs. yours, playing every card in your deck and hoping he makes the first mistake. They don't have to be mutually exclusive, but in some minds it is.
Understand Hang, this is not directed personally at you, rather the situation.