i completely disagree with the conquest idea, its essentially siege with more flags, the uniqueness of battle is that you have one life to do as well as possible and thus making that game much more exciting, where as siege i tend to jump on for a map or 2 and find myself bored because there is no real challenge to siege apart from spawning and dying over and over again. Conquest would be no more different, i still don't think people would swap class because they don't get enough xp, people will play the class they want to play and find the most fun, this is why you find all these agi rondel my old friends running around because people are bored of the combat system in M&B and find new ways to make fun. This is why a lot of people have changed from melee to archer because they have done everything they can do over a space of a couple of years in melee, of course the free respec did not help. The only way to solve the issue is to bring in a proper class balancing system or to Nerf ranged.
The problem with unique spawns is that it is going to give an advantage to killer classes no matter what the gamemode is about. If you can just kill the enemy team and win that way, it's probably the easiest way to win.
Actually in my opinion having only one life is a basic and absolutely needed requirement to have the new conquest battle mode have any positive effect at all! Because if not, it would indeed turn into a siege mode, and the player cooperation, which is a part of the problem, would sink to almost 0.
I think many people play the class which is the most efficient in their eyes, and not neccessarily the most fun or the best "flair". So if we change the game in a way that "hit and run" is not the most effective behaviour any more (guess why cavalry and archers and especially horse archers are such a pain in the ass for infantry), things will change. As an archer you can spawn, run a few meters until you reach a good sniping position and then keep on pewpewing until the enemy team is dead, especially if you have a lot of archer friends.
Now if there is suddenly a flag over there in those ruins, and the enemy has it, you can pewpew as much as you want, the few remaining enemies in the ruins will make you lose the game. You used to be a good archer, and you made a lot of kills per map, significantly weakening the enemy team and granting you a slightly positive W/L-ratio. But now, all you can do is move around the enemy flag, keep your distance, try to make a few successfull shots, but suddenly you don't have so much of an impact on your game any more. You lose control, and from an active role (you could fight by shooting all the time while the infantry had to reach you first before entering the fight as well) you slide into a passive supporter, who can't do much if your infantry sucks.
I guess this could be motivation enough for people to try to influence things a bit more by playing infantry again. And the funny part is: you know you don't need to kill masses of enemies to win as infantry - it's enough to hold your ground, stay defensive or be offensive in the right moment, and you can win the rounds. There is no need any more to deal with those horse archers or agility crossbowers or whatever.
Oh and btw. ranged nerfs took place since the beginning of the game a few years ago, and where are we now? I guess you don't touch tings which are put under voltage again and again, do you? So why do people always ask for nerfs when they SEE that it doesn't help ANYTHING AT ALL?