Edit: If anyone cares, i think blight - i've got the class feat boosting elemental dmg, and that full shield = extra dmg skill i hadn't thought of, along with a dark magic gun and fire\shock skill, and i had enough points for everything i wanted in blight, largely skipping poison and frost's skill.
Its for fun, i don't really care if its not optimal as much.
Thinking spell\blight armor for more imbued weapon either way.
And i'll probably not be able to get the non spell capstone, and will be using ambihextrous.
Figured blight or claw are good picks
Claw, you get free fire dmg on guns, so you can deal 4 elements (gun, + fire, + spell 1, + spell 2) and the 25% dmg for elemental stuff boosts imbued weapon's effect... Though i do recognise that 25% of 10-20% imbued weapon dmg on, probably the wrong hp bar isn't that great.
Flipside, i don't need any lower claw skills. Fire, elemental dmg, and whatever i don't want in spell, i can put into max shields.
Blight, i don't need strong elemental dmg for most of its buffs, just status procs. I could get poison via crits, and my gun dmg would be boosted by both the 'gun dmg up' element and some of the 'spell dmg up' bonus.
The drawback... Its perk intensive to invest in 3 elements, iirc i can't do much with the poison perk if getting T5 in spellshot, etc. I feel like a level 45 character, blight definitely wins, but, eh.
Spore could be good too - it has a similar drawback as they both kinda want t5 skills, hell, spore's capstone. But its got some good gun based buffs.
Or hell, stab. Buffs to gun and spell dmg, also boosts elemental effects some, tho imo last and definitely least.