AKDejaVu, point by point:
1 - "Would this promote vulching?"
can it be even more promoted??? anyway this will be compensated because the "vulched" country will not spawn over'n over.
2 - "Would this promote spawn point camping?"
Of course not, while vulching will be "promoted", spawning over'n over will be suicidal.
3 - "Would this favor the country with numbers?"
It depends, if a country with numbers sacrifies too much to force a reset by conquer, the other country will be able force a reset by casualities of the attacker.
4 - "Who gets more kills.. the country attacking or the country defending?"
Usually, both. But remember, the key is not just the number of "kills", but the perks gained. I may be killed three times in a 109F by someone in a Nikki, but if I destroy that nikki only once with my 109F the advantage will be for my country. Early planeset inmediately promoted. Flying and dying in "costly (while not necessary perked)" planes will be "costly" for your country.
5 - "Could a country win the war without ever capturing a base?"
Yep, as it should be. But base captures are rewarded also by perks. If you capture a base you'll be closer to the victory by conquer, but also by "perks". As in RL you can force a "surrend" by taking the territory or by causing tremendous looses to the enemy.