You know, I think you may have expended more effort in thinking this through than Tolkien ever did. Strategy and tactics weren’t really his thing; he never got above Lieutenant in WW1 mainly due to illness.
Herbert had the enormous advantage of being able to work full time on research for Dune. The suspension of disbelief required is no greater than for LoTR, and I actually think it is by far the better book, though the sequels aren’t in the same class.
The only thing I find problematic is that when you find some Islamophobes writing about Muslims, I suspect that they are actually referencing what they remember of Dune.
