The first draft is extremely important because this is where you figure out how long your screenplay is going to be and what you need to do in order to make it shorter or longer. If you come up with 40-50 scenes but they're not long enough to create a 2hr movie you need to add something to make it longer without losing your idea or making it boring and dragging the story along. That addition might be another character, a sub-plot or (for a Bollywood musical) an item number.
Remember only a fool tries to sell their first draft - no matter how good you think your first draft is - you can always improve it! I give myself a break between drafts. You'll be surprise how disappointing certain scenes become after the writer thinks about them for a few days.