We have been iterating a presentation for our new venture for months and months, and then just before we had to send out the first deck to a very serious potential partner, I re-wrote the whole pitch in just 30 minutes. New format, new colours, new sequence, new everything.
Unfortunately, you need those 6 months of pondering in order to pull of 30 minute trick. There are no shortcuts.
But on the positive side: if you have been using a deck for a very long time, you could give it a try and come up with a completely new visual approach for your story.