Arms had a lot of complaints in Legion, due to it's slot machine nature.
I came to enjoy the style though due to the Deadly Calm + Focus Rage combo, this allowed you to essentially game the slot machine, especially in Nighthold when combo'd with CoF. Your always watching that CD on Battle Cry and then BAM you go crazy and you have a bunch of rage to fish for procs with even after the CD.
Blizz decided Arms can't have nice things the next tier and nerfed Deadly Calm along with moving it to the same Tier as Focus Rage. However instead we had the set bonus in ToS to make Bladestorm a single target CD. This meant instead of waiting and gaming Battle Cry it was instead Bladestorm. Once it's off CD BAM! Your storming, and you now have a bunch of rage to fish for procs with.
It took me awhile to realize why Arms felt so clunky again, and it was due to the fact that I now have Tier 21. Now there is sadly nothing exciting about Arms. Before it was Battle Cry + Deadly Calm + FR, then it was Bladestorm, now I'm just praying to RNG gods. Mind you I'm lucky enough to have both Archavons and Ayala's, so I can't imagine what others are going through.