I think the tilt may have been caused when a planetiod hit the still molton Earth during accretion as the solar system was formed. This fantastic crash blew out so much rock and such that the moon was formed as these particles were drawn together by gravity.

I believe the Earth has about the same amount of water now as when it started. Even if all the polar ice caps melted, it should not change the tilt. Also, the continents are moving around all the time, albeit, very slowly. The huge masses of these plates moving around doesn't cause a cataclysm. Well, the building of the Himalyas is pretty spectacular but that, too, is centimeters at a time.

Something interesting I noted in my research during an Eng. class was that most, if not all, cultures around the world all have a flood myth as well as a creation myth. Makes sense because most cultures lived near rivers and many of these had a yearly flood.

Also, you'd still have freezing cold polar regions and it would probably be very hot at the equator.

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