Good idea for clubs on my F/D!
Trouble is, there are so many other great Druid spells, that she rarely enters close combat. She's the killzone damage over time dealer - after an entangle or two, she adds spike stone, one or more spike growths, and a static charge or two if it really looks bad, and then lots of ranged attacks (through a wall of webbed and entangled animated dead or other summons). Other good level 4 spells she uses often are: Static Charge and Giant Insect.
In fact my tanks / front liners only occasionally engage in close range combat, either.
The damage done in HoF mode by enemies is too dangerous, especially in "Call to Arms" areas! Non "Call to Arms" areas are much easier to deal with by kiting one enemy at a time back to the party / summons. It's also ALOT less magic intensive, but takes longer to clear out an area (and can get tedious...). But it's fun for a while
I can go a lot longer between cheesey rests (or healing spells or long waits for a slow Song of Sith regeneration), by keeping everyone out of harm's way.
Regarding backstabbing and sneak attacks. Sadly, they seem pretty worthless in HoF mode. The enemies just have way too many hitpoints for 4x or 3d6 extra damage to make a big difference. It's a novelty that's fun, but really doesn't add much value...
Maybe crippling strike will become useful at higher levels. But, a specialization just so you can sneak attack or backstab with a blunt weapon seems pointless to me (at least for now)...