dest/src order is not a big deal in absolute terms: The ISA designer picks an order, documents it, everyone follows their documentation, done. Intel picks one order for programming Intel, DEC picks another order for programming the VAX? Great, just look in the instruction set manual and you're set.

The silly thing is importing one order to another architecture that uses the opposite order. Now your users have to transpose operands for no reason. The really silly thing is messing up the operand order of the cmp instruction in the process. The VAX assembly language had a compare with the sane operand order, BTW.

Yes, that is the cherry on top, maybe.