A "simplistic model" refers to a basic or overly simple representation or explanation of something, which may not accurately capture the complexity or nuances of the subject. Full definition
That's a really simplistic model of the climate in equilibrium. (realclimate.org)
This is a very simplistic model of a very complex organ, but think of the brain in terms of two parts — an upper brain and a lower brain. (positive-parents.org)
With this in mind, rather than trying to make simplistic models to understand sea level changes, perhaps a better approach is to look at what the experimental data actually says. (globalwarmingsolved.com)