Bipolar,
I very highly doubt HTC will make any significant changes to curb the effects of ENY. HTC deliberately put ENY out there for game balancing reasons. When a country has significant numbers advantage, along with bases, it would be reasonable and fair to give the low numbers country a chance to defend with lower ENY planes. I also very highly doubt that AFK people have a big impact in ENY. I do agree that people who are AFK for longer than 20 minutes should be kicked. As this would help regulate arena caps, but not ENY.
Given your proposal, lets put this in perspective. Below is a random sample from a given moment of time in any of the arenas:
Knights - Players 150 Flying 135 Bases 30
Rooks - Players 165 Flying 110 Bases 45
Bishops - Players 160 Flying 125 Bases 50
(Let it also be known that those who are not flying does not necessarily mean they are AFK)
This proposal has a flaw in it. As you can see above, Knights are low numbers. But there are more Knights flying in the air than the other two countries. Knights also have the fewest bases controlled on the map. So would it be fair to the Knights to have their ENY nerfed just because they have more pilots flying than the other two countries? No. In fact, it would give the high numbers countries an advantage as more people can quickly re-up their low ENY planes and get an even bigger advantage than they already have. This does not balance gameplay in any way.
The best way to control ENY is actually up to the AH community, not HTC.
1. Can you switch countries? Yes.
2. Do you have to be married to the chess piece? No.
3. Does numbers affect ENY? Yes. And by a significant factor too.
4. Will ENY be affected after you switch countries? Yes.
So IMO the logical conclusion is that it is up to the AH pilots to regulate ENY by switching countries. The problem is that there are a lot of stubborn people who dont want to take the initiative in helping balance gameplay.