Hypothetical questions like that are hard to answer. There's no alternative to writing the constitution even if it means extending the deadline.
How much extra time would be necessary?
That depends on how efficiently the CA works.
Suppose it continues working at its current pace.
Look, in order to complete the constitution, parties much reach consensus on a couple of key issues: federalism, state restructuring and PLA integration. The parties must work hard to find common ground.
But even if they did reach an agreement, isn't there simply insufficient time?
It will be tough to finish the constitution by the deadline. Many subject committees still haven't submitted their drafts. Once they do, even if the Constitutional Committee spends only two days on each draft, it will take a further 22 days to complete the constitution. So it will be tough.
Constitution 2010, Nepali Times coverage of issues related to writing the new constitution