Concentrate can be helpful to have on a WW barb for times when you are out of mana, like a mana burn pack or enemies with low or no drain effectiveness that you can’t mana leach off of, but the single point you have to get as a prerequisite for WW anyway is usually enough for that, especially when boosted with + skills from gear. I typically grab Berserk as a 1 point wonder on WW barb to deal with PIs.
Depending on gear I could see throwing some extra points at concentrate or berserk if you need better AR, but I would definitely max WW, mastery and BO out first. 10 points into concentrate feels like too much unless you are a Concentrate barb.