Collocations for simplistic - adj.

appear, be, look, seem, sound

extremely, fairly, very, etc.
The graphics are somewhat simplistic.

grossly, highly, incredibly, overly
a highly simplistic generalization

a little, slightly, etc.
dangerously
This interpretation of the history is dangerously simplistic.

Simplistic is used with these nouns:
approach, idea, interpretation, notion, view