I don't think we are going to see 40v40 with this engine.
Of course we can see a 40 V 40 warzone.
The only problem is seeing it is all we could do as we would all freeze and not be able to do anything.
Could you imagine 80 abilities going off at once .... you'll be able to hear the servers cry for a quick death.
It's a shame really. Some people like small scale arena but i'm more of a fan of large scale fights. More going on, the stress, the hectic battles, the getting pounced on by 12 stealthers when the rest of your team zergers and you were tying your shoe lace.
I started with PvP in DAoC and loved the big battles in the lakes. I thought Illum would scartch that itch for me but sadly it wasn't to be.
The truly sad part is the game and the PvP crowd have the makings of some great big fights but we'd kill a server or two trying it.