Yes, it is pretty impossible to formulate clear rules for gear obtainability (just too many variables); they are decent guidelines when trying to decide if a build can be build by someone realistically. Personally, they helped me a lot in my early days of GD 
Because they are (imho) just guidelines, however, I’d suggest to just leave the rules as they are & to not take too many pains from worrying how they could be improved; in the end, loot drops are completely random in every individual case anyways, so how easy something is to build varies greatly from person to person either way 
Edit: thank you for adding my Cyclone build btw!