Yeah, arrow carts are all the rage because you can place them on top of a wall where nobody can hit it and rain down arrows but for open field fighting, the ballista is far superior. Way more damage per hit, way more DPS, extra-special-awesome if you can catch people in a tunnel or doorway where they have to come at you in blob/line. Their only weakness is that they require a target and direct line of sight to it, which limits where you can place them.
I didn't get to fight a single ballista this whole weekend, though. People just haven't caught on to their value.
We would capture a supply depot and then have some people stay back guarding it with ballistas and were massacuring hordes of enemies that way. They have to either build a trebuchet to destroy your ballistas from long range or else overwhelm you by like 5 to 1 odds. I really like that in this game "zerg + 1" does not beat "zerg". It's more about siege engines (and supply) than it is about pure numbers. "Zerg with 4 ballistas" beats "Zerg x2", no question about it (Zerg w/ 4 ballistas vs Zerg x2 with catapults and it might get interesting).
BWE2 showed good improvement in terms of bugs, framerate and balance but was lame for WvW because their matching system blew it. Each day it was us vs 1 pretty good server and 1 brand new server. The brand new servers were totally useless and the "pretty good" servers couldn't contain us 1v1, so it was pure roflstomps. (Although really "yawnstomps" is a better term because after rolling them, there was very little to do.)