No, we're not crazy. We do realize that richly descriptive and simple sound a little bit contradictory, and we do also realize that if you've picked up a copy of Samson recently, simplicity of language might be the last thing that comes to mind.
But hear us out. We're judging Milton by Milton's own standards, not by the standards and conventions of language today, which means that we think Samson is linguistically challenging and difficult to read, but also stylistically simple for Milton (who, by the way, is considered one of the most difficult—and rewarding—poets in the English language for a reason).
If you've been reading his most famous work Paradise Lost recently, you'll immediately notice that Samson is far easier to read. Instead of all the obscure images, symbols, and dense references that characterize almost every line of that poem, the characters in Samson speak directly and with a lot fewer bells and whistles. Instead of dropping random references, they spend a lot of time vividly describing things: other characters, scenes they've just witnessed, and most of all, their own interior feelings and beliefs.
When arguing with the giant, for example, Samson exclaims: "I know no Spells, use no forbidden Arts;/ My trust is in the living God who gave me/ At my Nativity this strength..." (1139-1141). It's not exactly Clueless, but you can probably figure out what he's saying.