WoC will be a mystery for awhile yet in many ways. Here is some info I have read (all rumors but from credible sources like Al Lutz at MiceAge) as well as some speculation on my part...
o DLR has restrictions on fireworks because of its Anaheim location. This is why the DL fireworks get cancelled so often. Disney wanted a DCA show that does not use fireworks so that they can show it reliably. Hence no pyro on WoC
o People who have gotten inside info on WoC say it may very well exceed Fantasmic
o DCA needs a night time draw and the DEP was not it. WoC will be it.
o Do not expect stadium seating for WoC. It will be like Fantasmic with terraced concrete to allow people to stand and watch.
o DCA was built on a shoe string budget and there were some who argued for a larger Paradise Pier lagoon at construction. Now they are stuck with the lagoon size that they have. There will be issues with viewing WoC. This happened with Fantasmic as well and Disney had to go back and change the viewing area. They are applying that knowledge to WoC but do not be surprised that they have to go back and make more changes to the WoC viewing after they open it. That will not be possible until Fall 2010.
o WoC will be super popular the first year. Expect the issues next June and August around AP blockouts (like what happened last month) to apply in 2010 in late June and late August. I would avoid these times in 2010. Go when the AP blockouts are in effect. This means the safer time to go starts sometime the last week of June until about August 20.
o DCA nighttime hours will be expanded. I predict DCA will have hours of 10-10PM for all high season times in 2010 and then in 2011 DCA will have its 10th anniversary and DCA may start opening at 9AM and staying open until 11PM for high season hours. A lot will depend on how much traffic DCA pulls. I think they will pull a lot more traffic come 2011 and especially 2012.