New Actions and Perks
Skills
Turret (Like Axton)
Perks
3/3 Secrecy (Upon activating an action skill you have a 30% chance to place cryo bombs on enemies)
5/5 Easy Lethality (Kill Skill, gives 15-25% crit dmg)
Line Em’ Up (Bullet piercing, if you kill an enemies by peircing through, gain a stack of Knock Em’ Down, Each stack grants a 30% damage bonus, Max stacks 3, stacks last 10-20 sec)
I can’t think of much right now, if some good ones are commented I’ll update this
A couple ideas come to mind for me, just throwing out my two cents for fun.
Tree: The Devil’s Spark - enhances grenades and explosions.
Skill: Land Mine/Claymore
–uses a grenade to create a grenade that lasts indefinitely until detonated. Can be detonated by enemies walking near the grenades radius or you shooting at the mine. Damage is increased if enemies trigger it. Grenade mod is applied. Cooldown 5 seconds.
Augument ideas:
–Truxican Truck Bomb - the land mine now actively homes into the nearest target in a mini technical.
–Brotherhood Flynt - the land mine now spawns 3 children grenades on detonation. A mirv grenade would gain 3 additional children grenades. Damage reduced by 25% and does not receive bonus damage on enemy triggering.
–Pour on the Feckin’ Chaos - The land mine gains an additional element at random, if the same element is rolled, radius is doubled.
Perk ideas:
–Ta’ pieces - 5/5, if an enemy is killed by your land mine, 50% of the overkill damage is applied to all nearby targets.
–Lucky Charms - 1/1, Zane’s landmine now has a 30% to crit.
–Mark of the Devil - 1/1, Zane’s bullets actively seek all targets affected by the land mine for 25 seconds.
Tree: Highwayman - Shock and Melee tree
Skill: Electric Net
–Zane throws a net that deals a medium amount of shock overtime and paralyzes the target in place. The target takes an additional 50% damage from all sources for 5 seconds. This bonus is doubled for melee attacks. If a target is too large for the net (bosses). Deals a high amount of shock damage instantly. Cooldown 20 seconds.
Augument ideas:
–Net gain - enemies killed by the net dot or melee trigger a passive ammo regen for Zane and his teammates. Cooldown increased by 10seconds.
–Nothing but net - Zane’s net no longer deals damage over time but a burst of damage at the beginning of the duration. Damage becomes neutral.
–Web of Deceit - The target and 4 nearby targets are affected by the net. Cooldown increased to 35 seconds.
Perk ideas:
–Whiskey in the Jar-o - 5/5, increases melee damage by 100%
–Olé! - 1/1, Zane’s melee attacks ignore shields, but not armor.
–Where’s me Jumper? - 1/1, Kill Skill - Zane gains additional movement speed and health regen based on the number of stacks. Max stacks 5. Lasts 8 seconds. 15% total movement speed and 10%hp/sec.
One passive skill that activates all kill skills when enemy gets frozen and another one that increases damage against frozen enemies.
Hehe 4th skills tree is not even out yet and you already discussing 5th tree. 
But to be honest Axton’s turret was my favorite skill of all times even thou it had such a poor damage scalling in higher difficulties for whatever reason. I’d love to see that one again and made properly this time!
Otherwise I would like to see some melee damage love for Zane. He has imo the coolest looking melee attack in the game, specializes in cryo element and freezing stuff, he’s fast and has the Barrier. Why there is not a single skill that would give Zane melee or general damage increase? It’s such a shame.