City siege changes are posted in the US-Forums. You can also check the write-ups of the trip to Mythic HQ by Shadow-War, Mykiel and Werit.
I don’t want to comment too much on them, because I definitely need more coffee today, but some stuff has to be mentioned.
The overall siege looks now more unique and special. No capture the flag, domination-stuff or something you know from scenarios. This is good. You could argue if defending/killing some NPC is 100% RvR Driven.. but with the math I know, I give them 97%+standard error..so this is 100% more or less. In the write-up Mykiel posted the Mythic staff agrees to that.
The only change that will result in a really great uproar is the single-queuing. So no premade warbands now in the city. I don’t run that often into city sieges, but having a correctly setup warband (especially when you get penalized for leaving the instance) is just too important. With single queuing, I hope that there is some cpu-time reserved for putting together some pug-warbands with the right mix of tank, dps and healing. Everyone knows how terrible things get in a scenario, where your setup is screwed, because of too many single-queueing.
One thing I’m really interested to see is the Champion system at the end of the siege. Sounds like fun.
I’m just afraid of the bug-champions.. Reading the write-up of Mykiel, it seems that the city siege content needs much more polish and Mythic already postponed some of the polishing to patch 1.3.6. Even though this are just cosmetic things they postponed..it is imo not a good sign.
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Zizlak (doomdiver.wordpress.com)
Zizlak's travel diary 
Ah yes the bug issue. Without doubt my biggest fear for this 1.3.5 patch. But as long as they aren’t show stoppers, then with a bit of luck then they can be handled with hot fixes. It’s a show stopper that would end up with a big plate of egg on face.
I’m actually quite postive on the break up off the premade warbands. It’s maybe an attempt to even up the playing field a little. No one wants to be in a one sided slaughter fest for the whole seige and a quality pre made group can be enough of an advantage.
Personally I have never been a fan of the warbands concept, it’s possibly the single thing I would love to see reversed out of the game as a whole.