I agree that some rewards should scale based off of the difficult of what you are doing in wvw but their needs to be a base amount of wxp and loot given. A steady ram up of rewards if you kill enemies in quick succession or without being downed would be nice. A kill streak system would need to help solo player get increased loot instead of forcing them to find zerg for greater rewards. Before rewarding wvwer based off of the difficulty of a capture or fight, A-net should really look into placing a comeback mechanic into wvw. It would have to make targeting difficult objectives for a weaker server more worthwhile. As for the AOE cap that is a hardware issue that A-net has stated that they can not remove it without creating more issues in wvw. In EB the biggest fights are SM fights and alot of lag is created because of the damage calculations. Unlocking the damage cap would increase the amount of damage calculation that the servers would have to handle creating more lag.
I tend to get 3-4 a month in wvw. I am sure you can get more than that doing fractals daily. Still is RNG some players are lucky others not so much ascended boxes are rare.