The strong arm I always really saw as a passing ability but it does allow big guys to access a throwing skill they wouldnt otherwise be able to. (hence it has to stay in strength skills as to allow big guys direct access to passing skills can be silly)

Multi block- I have never used myself effectively but then I rarely utilise deathrollers or big guys with strength enough to take advantage of it.
Break tackle is good for big guys and have used this quite a bit in leagues in the past
Juggernaut. not really had any experience of but its balanced.
Grab and thickskull I dont have any problem with but not my choice. Grab specifically can be very useful for positioning players to frenzy, or push away from an assist or even to help with pushing your players to help them get within touchdown range.