The reason it is scheduled to take so long to complete has nothing to do with them worried about "everything going smoothly" because they "rushed the project".
The reasons are:
• Spaced out openings. This will be the ONLY new attraction opening in 2014 in all of WDW. If it were to open in 2013, they'd have nothing new to open for next year. They had Princess Fairytale Hall for 2013.
• Budgets. By pushing it back to 2014, they're able spread out the costs over multiple years.
• Costs. The longer a construction project timeline, the less it costs. Construction companies charge less if there isn't a push for a quick opening and the slower progress means fewer man hours.
The project was originally supposedly delayed because it was a late addition due to the swap from Cinderella's Chateau. They started construction only a few months after the rest of the FLE, so there's no reason to think plans weren't ready to go by then (meaning at most, it should have opened only 3-6 months after the rest of the FLE).