Spent a few hours testing on Trouble. Sharing what I discovered.

• Trouble seems to have different kind of attacks by default with different values
  • Without class mods and specializations : basic trouble attack was doing 1228 damage for me with 0 skill points invested, no class mod and no apparent bonuses from outside sources.
  • Trouble seems to have a heavier attack that he usually uses after sprinting at someone, doing 1637 damage for me. I'm going to call this a lunge...
  • Trouble's range attack does the same damage than his basic attack : 1228 damage for me.

I'm saying "for me" just in case I happen to have a multiplier that I forgot to disable.

Oddly enough, Trouble's base damage is numbered at 1338 by the skill card, but in reality most of the hits Trouble will hit are going to be a bit lower than that, with the occasional slightly increased attack damage that he gets when performing a lunge. I didn't discover any other kind of moves when testing Trouble at the training dummies but I don't exclude the possibility of Trouble having a few more moves up his sleeve.

Badass Trouble does properly increase damage by 50% as advertized in the skill description card.

About Trouble's scaling :

• Trouble's damage DOES increase from Action Skill Damage bonuses. There's a lot of contradicting information going on right now about this with some people saying it benefits only from Skill Damage and other saying Action Skill Damage does work fine, so I'm saying it : yes, Action Skill Damage works and you can safely put points into Blood is Magic and fetch I Am A Gun from your specialization tree.
• Naturally, Trouble benefits from "non-action" skill damage bonuses such as the one you find on Ars Arcana.
• Action Skill Damage bonuses DO increase damage from command skills.
• Trouble does NOT benefit from gun damage increases in any way. As expected : gun damage will not boost his melee attacks, but it will not boost his ranged attacks either.
• Trouble does benefit from melee attack bonuses : nothing surprising here. However, and this was kind of a shocker to learn but at the same time it kinda makes sense : Trouble's ranged attack does NOT benefit from melee attack bonuses. This means you'll actually lose DPS if trouble has to use ranged attacks to fight something if you were using passives such as Fell Inscriptions or Blasted Fiends.
• Trouble does NOT benefit from minion fire rate increases such as Grave Assault. Not surprising.
• Trouble does NOT benefit from minion reload speed bonuses such as Idle Hands. Not surprising either.

Other tests :

• Because Trouble doesn't seem to have his ranged attack benefitting from melee attack bonuses, I wanted to see if Reverburnation could proc on Trouble's ranged attack. Response : no, ranged attacks will NOT proc Reverburnation.
• Trouble can proc status effects if he's attuned to an element. However, the chances to cause the effect innately are very low and unreliable. It's quite a pain in the ass to increase that too because the only way I found to increase status chance on minions is Fire Attunement.

Hopefully this will help someone.

Afterthoughts of these tests : the fact that Trouble only partially scales from melee damage adds to his pile of jank that participates at making him feel weaker than other abilities, and this might be one of the key reason why he feels incredibly inconsistant at time. This is especially concerning when taking into account the fact that a simple AI defect could make him resort to ranged attacks rather than melee, thus making him lose on a lot of potential damage. That kind of behavior can be especially common when pitting Trouble against larger enemy boss. Naturally, this flaw also makes Trouble lose a ton of damage when fighting any flying enemy. As if Kratches weren't annoying enough...

I think it would be welcome to make Trouble's ranged attack properly scale off melee bonuses while also being able to trigger and benefit from melee focused mods such as Reverburnation. This would be done for the sake of making Trouble more consistant, and thus less frustrating to use.