Elon Musk on Twitter:
Mars V2 plan coming soon, which I think addresses the most fundamental flaw in V1: how to pay for development & operation of giant rockets
One way to address that: avoid paying for development and operation of giant rockets at first. Starting with a smaller, Raptor-powered vehicle that could fly from 39A with minimal infrastructure changes would be a good idea.
Scaled hardware to validate the architecture, big enough for initial Mars missions with a few crew members, and small enough to be used commercially for other tasks.
And to make things really interesting, give it a payload capacity similar to SLS Block 1B.