It seems to me that the basic problem that drives all of these considerations is the ability of defenders to up unlimited planes from the field. That's why taking down hangars or deacking and vulching is so important and effective. That's what drives the hordes and NOEs. It's simple math. As long as the defender can instantly re-up while the attacker has to fly 5-10 minutes to return if he's shot down, the defense will easily win any battle of attrition by sheer weight of numbers - numbers meaning sorties. If you don't care how many times you get killed, you can up ten times, get vulched nine times, kill one plane the tenth time, and still be winning the battle, because that one kill is one attacker out of the fight while the nine vulches don't take any defenders out of the fight (because they can just hop right back up ten seconds later). If 10-15 guys do that, they may get killed 100 times between them, but they'll eventually kill all the attackers, or at least enough to beat the attack. It's effectively a force multiplier for the defender: one player equals as many sorties as he is motivated to fly. Therefore the most effective tactic for the attacker is one that keeps it from becoming a battle of attrition, which means bringing overwhelming force to smash down the defense before it can get started or dominate the field so thoroughly that defenders can't (or are unwilling to) get up to get even that one-in-ten kill, or sneaking in and taking the base too fast for the defenders to react.
That's why the best furballs are usually halfway between two bases - because a kill takes the victim out of the fight regardless of which side he's on. That's great for furballing but strategically inconclusive, because there's no objective for the attacker out in the middle of nowhere. In order to take the base, you have to push the fight to the base, and once you do that you're back to the defender having a big advantage.
It's also what makes CV-based attacks so intense - because the attackers have a base very close to the target, so they can re-up as easily as the defense. The attacker can win the battle of attrition if he consistently outfights the defender.
Making the base more secure and the town more vulnerable doesn't really change that. One way to address it might be to move the towns much further from the fields - say, halfway to the dar circle, and generally toward the other side rather than toward the defender's HQ. Do that and make the field more secure (more ack, more or harder-to-kill hangars) and you've changed the math. Now it's much harder to stop the defenders upping at all, but the defenders have to come well away from their field ack to accomplish anything. Now the attackers' best tactic is to beat the enemy in the air, not keep him from getting into the air to begin with.
Another way to address it might be in combination with ideas from other threads like zone ENY or ENy linked to the number of people upping from a given field, or changing the percentage of town destruction necessary for base capture based on the number of attackers. Do that, but also change it based on the number of defenders too - and the number of sorties, not people in the air at a given time. 50 attackers would have a high ENY, but so would 50 defenders - or 10 defenders upping 10 times each. You can keep upping all you want, but as you do your ENY climbs. In the 50-10 scenario the attackers would still have the higher ENY, but where the number of attackers and defenders is more even, but the attackers are outfighting the defenders, the defenders' ENY would climb as they get killed and re-up. That would give an more even number of attackers a better chance of capturing the base by winning the air battle. it would mean killing a defender actually accomplishes something strategically.
Another possibility might be to puta time limit on re-upping from the same field. If you get killed, you can go and up anywhere else on the map, or go to the next nearest base a sector away and re-up at once, but if you want to up at the same base you have to wait five minutes. Again, that would stop the defending base from having effectively an infinite number of planes to defend it, and it would mean killing a defender actually takes him out of the fight for a little while (either in the tower or flying in from the next sector). And again, this would also work most effectively in combination with measure to limit the number of attackers, or handicap the attackers (ENY, town capture %, etc.) if they bring huge numbers.
The basic idea is to limit the number of attackers, but at the same time limit the ability of defenders to win the battle just by re-upping infinite times and eventually getting lucky. The attackers need to beat a more equal number of defenders if they expect to win, but the defenders need to stay alive and win fights rather than die-reup-die-reup-die-reup-rinse-repeat if they expect to win.
