I deprecated them a while back when I started to work on a lot more mobile stuff. I was seeing all sorts of implementations, many inaccessible, which was unacceptable. At that time fixed positioning on mobile was almost non-existent so lightbox style presentations got the bin.
It was a very uplifting experience. Removing one or two presentations from your arsenal can really make you think hard about the content. Does the content *have* to be shown that way?
What is the requirement for the content? To be shown inline on click of an action? There are alternatives that don’t force an overlay. I still use tooltips, accordians, various show / hide UI elements.
I’m not sure what your JS dev is like but if you are using jquery I’m sure you could find a window resize plugin. Building one wouldn’t be too bad…Just on resize and a change bool and target the dialog container(s) for resize
Chris Coiyer worked on [http://fitvidsjs.com/](http://fitvidsjs.com/) would be pretty good for your videos
I’m kind of getting into the same school of thought as @cmcp is in and ditching that idea as well. It was cool for a while, but I think there should be creative new ways of doing it that work better for rwd.