I've been having issues with fitvids killing views admin as well as other jquery and ajax admin functions.

I pulled out and uninstalled the fitvids module but left the css in place on 2 sites today and noticed that both vimeo and youtube iframes still maintained the same responsive behaviours without the fitvids installed.

I've checked my html output to make sure it wasn't in any cached versions and cleared caches and it still works fine.

If I'm correct then it looks like youtube and vimeo have changed their iframe code and it may be possible to never need this module again if the video supplier's iframe is compatible with responsive sites.