By "Versatile", max means masteries that can do pretty much any gameplay style.
Probably any combo can be legendary viable, it's all down to how you build them.
Conqueror for example, isn't versatile, since almost all skills and passives rely on melee weapons and shields.
Yes you can try but unlike other masteries, you really limit your skill range this way.
I think most are pretty versatile as long as they don't have skills and passives for specific weapons. Spirit isn't too bad since it only has one weapon skill and upgrade (compared to defense which has a ton of shield skills and passives)