I've been contemplating the same thing for a few months, for exactly the same reasons. My user ID on my store account is a little more... abstract, I guess 
So doesn't resemble much at all except some song lyrics I really liked at the time I joined. 
The main reasons I haven't changed the ID is because after 30 days, no one will be able to find me by searching for my old ID (repeat customers are a really big part of my business, so I'm loathe to do anything that makes it more difficult for people to find me, even though my store name would remain the same and is more likely to be what people search for), and because I've seen more than a few threads on the boards where members seem to think a user ID change is somehow suspicious, even though nothing on the account changes in anyway except the name, and ID history can be displayed via the feedback profile.
Eventually, I'll probably just go 'stuff it', and change the ID, probably during a peak time so that as many people as possible might notice the change.
(Re store name and user ID matching - it can be done, but you have to do it in the right order as eBay will block a store name from being created that's the same as a user ID..... or maybe it's vice-versa 
Sorry, I can't remember for certain which way it has to go).
True, although one of the sellers I follow changed their ID too, and when I saw them in my list of following I thought "who the heck is that and why have they appeared on my followed list?" (I did figure it out, after checking what they sell, but nearly deleted them without doing so as I thought they'd popped up there from an old eBay search or something).
(Re store name and user ID matching - it can be done, but you have to do it in the right order as eBay will block a store name from being created that's the same as a user ID..... or maybe it's vice-versa Sorry, I can't remember for certain which way it has to go).
Id first, then you can have the store the same name.
