Honestly didnt think they would do another beta, I will give it another go but its going to have to be vastly improved compared to the last beta if they are going to convince me to buy it.
No one expected an open beta given the last launch date but it's pretty standard really. Alpha, close, open....natural course of MMO releases.
Nothing much will have changed so don't expect it to. There will be bug fixes for the exploits found and perhaps some quality of life changes but the mechanics won't have changed in 4 weeks. This beta is likely just to be about numbers testing to see where the limits of the servers are and whether any changes they've made to the War instances have the desired effects.