I work at the Everett plant as an Inspector on the 777 flightline. The main concern for 87 now is...fasteners. They do not have enough. They are a different type for composite to aluminum and the process for making them has not been perfected to the drawing standards that Boeing has specified. Next...as mentioned before is the wiring. It's not that there is a lack of wiring, there's a lack of WHERE to put the wiring. No brackets, no or incorrect process specs for fiber-optic installation. Another part is payloads. Payloads is all of the installations that make up the airplane before delivery including interior packages, seats, type lighting, entertainment system and so on.
There are 2 787 "shells" in the factory. #1 plane is the one we saw on the news. Boeing has decided to destroy that plane in a static test (wing busting). This is something Boeing never does with a #1 first of model. Every 1st of model (#1) that Boeing has made after 1962 was "saved" of sold to other customers. The only model they still have (#1) is the 1st 747 at Seattle Field. So, the 787 will be the first #1 plane since 1962 to be used on static testing. Now...#2 will be the sold/delivered plane as so far, but that can change.
The bottom line is that Boeing has never built a plane like the 787 before. The processes they chose to build it is innovative and "unprecedented" as far as Boeing is concerned in the way they make planes.
I happen to agree with the time frame. They said 6 months (180) days. I'm betting 150 days or less. Payload items are coming in as I type. Things are going slowly, but it is getting built. Boeing is "famous" for giving more time than necessary. It looks good in the papers and boosts stock if they beat a deadline by a significant time.