Reading US forums and not having possibility to post on them, I want to say, that you already can toggle on/off HP bars in game without using Options with HP-bars modes.

One player suggested this at HOTS Beta US forums
http://us.battle.net/sc2/en/forum/topic/6893799530

Because I can't post here due to EU account only, I'll say here a small instruction how to toggle HP bars in game.

1) Rebind HP-bars hotkey to double-hotkey. I mean from ALT (default hp-bar hotkey) to SHIFT+B or ALT+`. Lets look at SHIFT+B combination
2) In game press SHIFT
3) While holding SHIFT press B
4) While holding B push out SHIFT
5) Push out B

Thats it! At same way you can block camera rotation, if you rebind it to double-hotkey combination.