I plan on being a templar in my next playthrough, and from what I've heard it has AoE detonator combos that work on everything for big damage.
Also, the only remotely challenging fights that don't include demons are Haven and Dragon fights, and you won't even have specializations for Haven. Everything else is rifts/rifts/rifts.
Edit: Furthermore, and a little off-topic, I think the templar class fits the theme of the inquisitor almost too perfectly. A templar, who specializes in destroying demons and suppressing magic is given the power to disrupt/destroy magical rifts and stop the influx of demons. It makes sense. Plus, the look and carriage of a templar just fits the role of leader/king quite nicely.