Ive never done a trip to WDW alone but I dont think I would really have a problem with it. I agree with the above posters, you are free to do what you want, when you want and can really enjoy all the little nuiances that we all miss in crowds or the hustle and bustle of a group. I always see something new or find a place to eat/drink everytime I go, so there has to be plenty of little nooks you can find.
I will disagree with the notion that WDW is a bad place to potentially find a signficant other tho. Look, many relationships are based on looks/sex/etc, but here is something you may have in common with someone already, aka WDW. Plenty of those are based on things which lack a bit of substance. There are plenty of places you could meet someone I'm sure (maybe not the Disney Big Top or even Fantasyland), but there has to be.
Overall, I'd do it. The way my situation if going, I may be down there taking my advice. LOL Good Luck!