I don't think he has much critical acclaim because his work isn't very conceptual and didn't fit in with the popular art of it's time period. Most of the time art critics like to lump a group of hot artists together and call it a "movement" and give it a name. The movement popular at the time when Escher was making most of that work (late 1940s-1960s) was "abstract expressionism" and he was basically the exact opposite of what they stood for. They were all about expressing emotion through the way you move paint around a canvas, and art as art itself. They didn't think art should be used as a tool for representing something from the real world. I'm talking about people like Pollock, DeKooning, Kline... and Escher's work was basically painsakinglly rendered math and science problems. Because of that he didn't get much critical acclaim in the art world, but he was really famous with people like mathematicians, scientists, and high school teachers. I don't really enjoy his work because it's so cold, and I hate math/geometry. But there is no denying he was a great artist and a brilliant mathematician.
He has enough fame I think, you shouldn't feel bad for him. I mean, I hear they are even talking about his dead ass on gun forums...