I think the ability to jump into something you are unfamiliar with and make it work might be the biggest thing for a senior DBA.  After 12 years of this there are still some gaping holes in my skill set, but none that scares me if I need to do it.

Also the ability to apply previous knowledge to new situations is one thing that I value,  but that is not really a senior position trait, but for everyone.  I try to teach the developers I work with how to write, and nothing is as infuriating as the same question being asked over and over.  I had this from a junior DBA back in the dotcom days, drove me nuts.  I think eventually he went back to being a teacher.

Also don't think the number of years make that much of a difference.  If you have been in the same job for 10 years, you might be very good at what you have been exposed to, but be very limited in the width of your knowledge.

One thing too, is the ability to know when you do not know.  Personally I think I know a lot less now than I did 8 years ago.  I had ALL the answers back then