If SQ really wanted to...
They could have kept everything (trans, break, ect) and installed a variable speed motor like GE did:
This way they can do a slow spin to wet the clothes, then a controlled agitation on low water.
The more I think about this the more I am starting to feel iffy about the design choice. I mean other manufactures in the same position have done everything else besides an agi tub when faced with the same challenge.
In regard to the DOE regs, my best guess is that the other cycles can still do a deep fill. Honestly, had it not been for all these regs, I think transmissions would have been around much longer for many manufacturers.