Shade needs funding...much more than other pirate classes just to be mediocre. Don't get me wrong i like shade's story, but range sucks. Ark is pretty good though and has a decent backstory. So go with Ark if you wish.
i'd say zero is still good at being unfunded, u can get the weapon to unique w/o cubing. also the wpn is fixed as 2ndary as well so the potential is doubled. Plus if u want the Emblem as well, u hav to go through the story line as well for coins to trade with.
I've had pretty good luck with Mihile recently, but from my experience most classes with epic 6-9% main stat on all equips do fairly well. Coming from someone that's got every class to 140, I really only didn't like Mech due to the constant need for upkeep on bots but that's just my opinion as I probably had bad bot placement to begin with.
I think outside of BT/Jett whom have some broken things, every class is pretty usable in endgame content.
I feel that you should define what you feel is "best" first and then go from there.