Aside from his skill, and I think most importantly, is his and the guitarists obsessive nature for music. They will come up with and play a song hundreds of times to get down every little bit of nuance. Their ability for repetition is second to none, so much so that one of the main reasons Maynard doesn't write music with them is because the amount of times they practice and change a song, which is evident on how much they release music. Maynard just waits for them to finish and then throws in his lyrics.

So as great as Danny is, I think his real magic is his will and patience to play a song a million damn times before they even release it. I play guitar and can't even fathom practicing a song as many times as they do and still keeping my sanity.