Not sure I follow. DSA requires a modular inverse algorithm which RSA doesn't (beyond that both are reliant on modular exponentiation and prime generation as the only "hard parts"). DSA has more algorithm parameters. It's just a more complicated scheme to implement any way you slice it. DSA requires more "units of mistake", and is more likely to be screwed up by the programmer.
Ah, I see where you're coming from. I have a mental shorthand that basically says "DSA is the one that works like DH", and you're right, you need the inverse for DSA.
But regarding failure modes, I'm thinking of (as a starting point) things like:
http://www.ams.org/notices/199902/boneh.pdf
There are a lot of implementation errors that happen with RSA. What's a comparable list for DSA? Failure to generate good nonces, and then...?
I agree that it doesn't matter though.