1) It took me longer to create blueprints than it would have taken to write the equivalent code. I kept finding myself thinking "I could do this in 5 seconds with a couple of lines of code"
2) The blueprints quickly became unwieldy. A tangle of boxes and wires that I couldn't decipher. I find code easier to read, as a rule.
3) I didn't find it any simpler than writing code. A Blueprint is basically a parse tree. It maps pretty much 1:1 to code; it's just a visual representation of code.