I went so far as to present it at a guest lecture in The USA to an audience of planetary scientists.
They were very polite. They told me it was essentially impossible, but gave me credit for trying.
- The killer argument is that the studies of the Proto-Earth - Thea collision show that yes, a lot of material gets lofted into orbit, forms a planetary ring, and condenses into a moon, but 90% of the material falls back to Earth, so it's impossible to strip-off more than 10% of the crust. The sort of model you're going for needs 70% removal. You can discriminate between metal core and everything else, but that's it. The surface stuff can't be peeled off and collected.
- Even if it was, the Earth wouldn't stay as a featureless globe. Plate movement and volcanism have been conclusively shown to dominate over sedimentary transport. The nature of the Earth is to scrape its continents together into as small an area as possible.
Learn about Plate Tectonics and Geology. it's a widely-researched science. Your comments about Australia and the Himalayas are so wrong they're "not even wrong".
Where do you think Granites come from?
Why do you think we don't talk about "Geosynclines" any more?
Why should the Earth stop being a dynamic system after a collision?
Why should there be any granite left?