I disagree. I think that Katherine has a favorite mode of manipulation (getting guys to fall in love with her) but you'll notice, she only uses it on the guys it works on (Damon, Mason, that random flashback Lockwood). We've also seen her manipulate Stefan with the reverse (by saying she's in love with him; whether or not she's lying, I think it's clear she knows the effect her words are having), manipulate Caroline and Elena by threatening/harming the people they love, and straight up compelling people when it's most efficient.

Basically, Katherine is too effective at manipulation people into doing what she wants and turning bad situations to her advantage to be a one-trick pony.

In short Katherine is ~awesome~