I can’t say much about the various types of software that are out there for editing/creating websites. OK, I admit I am a dinosaur in using FrontPage (I do have Expression but I’m too lazy to install it.) And I find Wordpress is really easy (once I read the instructions). So there really is no excuse for not being somewhat in control of your website.
I think it’s inexcusable when people say they’re being held hostage by their designer. First, make sure you’re the one who owns the domain name. You’d be surprised at how many sites I’ve helped the owner wrest control away from the “designer”. I try to make sure that even though it may be my email address that things come to (it never changes while other people’s do), they are listed as the owner. Maybe I’m still carrying around emotional baggage from the early years.
Second, make sure that you can get into your site and make changes if necessary. I spent a lot of time with clients teaching them so they could. They may never have to touch their sites, but when I had a major stroke in 2008, few people had a problem making changes and I was pretty useless for a while.