When you were trying to cast Intervene at the beginning with the turtle, your pet failed to Intervene because you had it targeted, so it was trying to Intervene itself. However, if you were to target something else, such as a party member or yourself, your pet would have tried to cast Intervene on your target instead. This is true for all pet abilities, just like for player abilities. You cast spells on your target.

You may want to suggest and/or try out the following macro. This is a minor variation on a common Warrior macro for use of Intervene while fighting or tanking.

/cast [help] [target=targettarget,help] [] Intervene

This macro will cast Intervene on your target if friendly. If your target is hostile, it will try to cast Intervene on its target instead. It makes it much easier to get an Intervene up on the silly mage (or hunter) who just pulled aggro on the mob you are attacking, without changing your target.

There’s something I don’t think you’ve mentioned in your videos or podcasts that I’d like to point out: Pets require less feeding with certain pet talents now. Ferocity pets get happier when they do damage. Tenacity pets get happier when they Growl. Very cool IMO, because I didn’t have to feed him once while stomping through Sethekk Halls with a resto shaman.

(One small thing for Thoreau: http://www.merriam-webster.com/dictionary/hearth

It rhymes with Darth or Garth. Join the Dark Side and party on!)

(One small thing: it’s not a HEARTstone, it’s a HEARTHstone. Hearth, as in place where you can light a fire and cook stuff without burning down your house. The word rhymes with birth and worth.)