This is the obvious "best" solution for those that Chrome/ium never floated their boats (me). Too bad that two huge browsers side by side are needed. One of them just to watch videos.
As far as this goes, can't one user have
iceweasel/firefox set up with multiple profiles? So anyone can have iceweasel non-flash for everyday use, and iceweasel with flash for videos.
Pretty sure I have seen that done for privacy issues - a mozilla profile that is set up for privacy or actually in a sandbox.
Edit - Confirmed.1. Create a directory for your flash profile (optional)
2. Run iceweasel -P to create the profile, store the information in the directory created
3. Make sure the profile you want started by default is checked - default is to switch to new one
4. Run iceweasel -P <Name of Profile> to start iceweasel with the flash video profile
5. Create a plugins directory in the new iceweasel profile directory created in Step 1.
6. Install flash plugin to directory created in Step 5.
Should now have a flash-enabled iceweasel profile for watching videos; make menu entries, key bindings as needed.