This has been a really interesting thread.
Pat, I, too, would like to encourage you to open just one or two dolls and play with them. I was the same as you are with the "fear factor" of reducing value until about 8 years ago when a special friend who lives near me, that I met through the Internet of all things, got me to take this step and taught me how to finally enjoy my collection. Once you actually get a doll or two released, it is amazing how quickly the "fun factor" kicks in!
I do have dolls that are boxed because I like the way they display that way, such as the already mentioned Star Trek set and the Harley #1 Barbie. I also have some dolls that are boxed simply because I don't have enough room to display everything at once. I try to rotate boxed dolls and rotate the larger fashion dolls as well. Space is at a premium for the larger dolls, so even when they come out of their boxes some of them have to go back in for short periods of time.
Some of the boxes I keep and some of the boxes I throw away. Some of the boxes are kept for awhile but then I get in a cleaning frenzy and pitch them as I realize I will never, ever part with the former occupant, LOL.
I have dolls in almost all of the rooms of the house. My kids always told me they were afraid to go away to college because they thought they would come home to find their rooms usurped by dolls. You know what? They were right, LOL!