The NSA is believed to have strengthened DES by making its substitutions more resilient against differential cryptanalysis. Careful with with words like "clueless".
On this point I'm inclined to agree with Schneier: why inject backdoors into things, leaving fingerprints and betraying both opsec and tradecraft, when you can just sit back and watch the software companies build the backdoors for you? NSA has as much as come out and said this at keynote speeches already, but it seems pretty obvious from my vantage point.