I recently went through a similar dilema. I wanted to repaint cement-block walls in a basement bathroom, and was concerned about various imperfections showing through. A professional painter-friend of mine suggested I "skimcoat" the walls using, I think it was, drywall compound. I didn't really know how to do that, nor was I entirely convinced it was a good idea.
In the end, I put on two coats of primer followed by two topcoats. I've been *very* pleased with the results, and am glad I didn't bother to skimcoat. Imperfections are still there if you bother to really focus on the texture behind the paint, but the results are more than good-enough for a basement wall, for me anyway.
So you might consider just painting. It is, after all, just a basement. "Just paint" worked for me. I guess that's all I can really say.