You have to be decisive. Indecisiveness is a startup killer.
Most investors are obsessed with the market size today and they don't think about how the market is going to evolve.
The thing that kills startups at some level, is the founders giving up.
... but the pendulum has swung way out of whack here. A bad idea is still bad, and the pivot happy world we're in today feels suboptimal.
The company just needs to see you as like this maniacal execution machine.
In YC experience, 2 or 3 co-founders seems to be about perfect.