New 50 Monk, questions

[Aeliott]

For cross class:
Blood For Blood (DPS boost, just be wary of the added damage taken)
Fracture (nice additional DoT, use after Demolish as both 18s. Leave out when TP's an issue though)
Mercy Stroke (extra damage to weave in)
Invigorate
Bloodbath (may as well, Impulse Drive isn't really necessary)

Pretty much all others are pointless outside of soloing.

Do back combos when possible, usually just Bootshine when Dragon Kick is up. Can do True Strike also if you have high skill speed. Most of your stuff is done from the flank though, yes.

Never use Arm of the Destroyer for anything other than the silence effect (which only occurs in Opo Opo stance). And you only ever really need to do that in Turns 1 and 2 of Coil. If you have to AoE use Howling Fist and Rock Breaker. You can use Perfect Balance to enable Rock Breaker spam if you wish, just watch out for the massive TP drain.

That said, Arm of the Destroyer is your only non-targeted ability, so if you have pop-up issues in FATEs or something it could be viable there.