No, not at all. Catch-22 isn't easy to read, and I think that this is partially by intent. It doesn't run in chronological order, in fact the timeline is so disjointed that Heller had to create a spreadsheet to keep track of what the characters were doing at at different points of the novel. (I'm not making that up, I saw a copy of the spreadsheet. The short version of a long story is that one of my college professors was a friend of Heller's, and had a copy of it framed in his house.)

Oh, and regarding the sequel (Closing Time): Now that I'm within 40 pages of the end of it, I'd say that if you've never read it not only is it not a sign you're unsophisticated, it's actually a sign that you've got good taste. (It's been a disappointment.)