No solution at all to this problem. Whatever it is, its not gonna work - or, not gonna work fast enough to make a difference.
Numbers fluctuate between countries during a span of certain time. One must understand this as a social phenomenon than just a simple game.
In the old days where the prime time arena was like 200~300 people max, everybody knew everbody. Every squad knew everysquad. To the problems of one side the pilots of other countries empathized. The community was tied a lot closer to each and every member, and thus self-regulation and organization was usually enough to balance the meager problems concerning pilot numbers.
The problem is, AH has grown out of that stage.
If the "good ol' arena" we all cherished was a small farming town, the current AH is like a large metropolitan city.
As the numbers grew, so did the anonymity.
Notice how channel 1 banter is a lot more hostile and severe than it used to be, not to mention frequent. In the old days, everybody knew everybody. The chances are that human beings are usually nice to someone they know. However, as the community and the arena grows larger a lot of people you don't know are playing the game with you. You feel less obligated to help them play a fun game, than emphasize on things such as internet etiquettes, manners, voluntary balancing of numbers, etc etc.
It can also be said that the three different countries, and the pilots that inhabit it, are a lot more competitive towards others, and also more oriented towards the loyalty to his own country than common good.
It's like the formation of Nationalism between the 16th~20th centuries. In a sense, the MA is indeed a "war". Ruthless attrition is what wins the war. Huge numbers advantage doesn't mean a "terrible game for fellow gamers" like it used to. It merely means "an effective display of power to crush the opposition". More and more people are anonymous to each other, and the spirit of social and communal interaction is usually limited to the strict borders of one's own country.
The veterans 'lived' at a different age. Now, the arena easily goes over 600 people at weekends. About 60~70% of the current AH population are 'newcomers'. Basically, AH doesn't "belong" to "us" anymore - whether we like it or not.
The more average gamer, who recently joined AH, has no prior affiliations with other squads and other countries. He comes into the MA, a new society, and he naturally attaches himself to the people that immediately greet them. Why should he care about the other country or their pilots, who are no more than mere enemies that should be shot down? Sacrificing his current ties and relationships with the people he know, within his current country?
....
Now, in a real world society, as such problems grow, people come to realization that a common rule is needed. They gather around and discuss things, come to a consensus, and set out some things which should be changed.
However, since no player has any kind of authority over the society in a game, the power to change things for the common good is solely concentrated to the developers, and they alone can make changes that matter.
However, since the HTC staff has to look out for people of all three countries, their decision can be only influenced by a unignorable, huge public opinion. They'd definately not make quick decisions.
Another thing to consider, is that any sort of "changes" made to the MA concerning numbers, has a high chance of regulating or limiting certain freedoms the player used to have.
Basically the numbers problem is a freedom problem - where the individual freedom of certain players of a certain country, in a collective level, unfortunately hurts the rights of other players of other countries.
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So any fundamental change would have to come in this order:
1. Almost all members of AH players have to start realizing that certain aspects of their choices should be limited, or reconsidered, for the goal of common good.
2. The collective opinion and consensus concerning the common good, has to be addressed and requested to the developers.
3. Certain aspects of reality concerning warring factions, should be requested to be implemented in the game, following the above defined procedures - basic organization, difference in operating sectors, a system that might limit the choice of a players country according to numbers, etc etc etc...
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Basically all three of above must condition must be fulfilled for anything to change. People must collect the overall opinion of their countrymates, it must be addressed to the developers, and they must also come up with an alternative method to implement in case the change is sanctioned.
Dividing arenas might work, but its basically a retro solution - sort of like, "if a metropolitan city has problems, then drive it back to the stone age so the people are all split up again".
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So, are we willing to accept the consequences of what we ask for? I'm guessing not.