Well, if you look at canon Sabers:
Artoria, Mordred, Siegfried, Gawain, Fergus, Altera, and False Saber have powerful ranged attacks capable of oneshotting an enemy at range if need be. Nero has the ability to force opponents to face her in direct combat - a dangerous proposition for any Servant. I honestly don't really know about Gilles, le Chevalier, and Caesar, so I won't mention them. None of the above, however, have a NP that will kill them if it doesn't land. Most of them also have some mobility tool or another.
The 1* rating could also reflect a low cost; her NP seems to function on a conceptual rather than raw power level, making it relatively inexpensive to use.