There are two other areas that are just as important.
One of them is what, I think, the Japanese call kokoro. Heart/spirit. Dan has that in abundance. His skills/abilities far surpass most, but yet here he is trying to explain, again, to Chris Hein about IP/aiki. How many times has he done something similar with other people? His training atmosphere is open, friendly, helpful, and everyone just works together to get better. That's everyone from any martial art and any school from beginner to top echelon. He'll work harder and longer than anyone there to get people actually doing what he can do. He'll spend time trying to figure out ways to get the material across better or to help one person overcome an obstacle. His power is off the charts but he doesn't wield it like a bull in a china shop, instead, like Ueshiba, he shares the same vision of a better budo where power is used responsibly in a manner that avoids unneccessary harm. Yet, he still looks at his own level and progress, shakes his head, and says, I suck. All heart and spirit.
The other is his ability to teach. You can see progressive levels in his students from a few years to twenty. As Dan is fond of saying, it isn't about the person but about the material. Training with Andy brings those words alive. On any given training day, you could replace Dan with Andy. Slightly different teaching methods, but you're still going to be able to get to where they both are *if* you put in the time training. That's a great testament to Dan, his realization that it isn't about a person but the material, and to how he's been able to actually transmit that to many other people. Qualities of a great teacher.
While, I agree, that he's the best martial artist I've ever encountered, I think it's all three things that make him stand out.