Amemet +1 is a perfectly good back piece til you can obtain Cuchulain mantle/cerberus Mantle while subbing /nin(engaged). Unless you already have a foragers, or getting it for your DD jobs, just for pld is a waste vs amemet+1 or cerberus, just b/c cerb mantle can be used for ja/flash/etc and fire set.
When you arent subbing /nin, Shadow mantle/boxer mantle will do you better to migrate the inc damage you will be taking.
If you can swing your sword at a mob, there is no reason why you should not be DD-ing it with DD gear. What else are you going to wear? enmity, does nothing, vit/def? wont affect much against mobs of higher level, shield skill? unless while shadows are up, HP? also 90% useless while shadows are up, or unless in a perma spot, soon as you macro it out, you lost 80% of its usefulness.
Being a good pld, you need to macro efficiently:
TP: acc/haste/refresh/att
flash: haste(til you cap your timers) enmity
JA: enmity
Cures: enmity
ni: haste noblinkable shield gear if you want
ichi: haste/shield
ohshi noshads/terror: Shield/damage taken gear, when you have nothing left then vit/def
Rampart: Vit/enmity
:note: most pld gear is built with HP so wearing HP gear isnt the most efficient thing you can do as youll macro it out anyhow, but if you arent sure of yourself or healer, HP gear is fine, just keep it on you perma to make the best of it.
DD pld is a great thing, it produces better results on HNMs than it does in exp, however, that doesnt mean you shouldnt gear for DD in exp.
Stay focus'd, spam your hate, cure yourself(very important, stop draining your whm/rdm's MP), count your shadows, learn to blink your shadows, know your enemy.