I posted this as a reply elsewhere, but I figured I'd make a dedicated suggestion for the, too. Right now, the shocktrain arcs can be extremely oppressive. The arc range is fairly long, so avoiding becoming vulnerable to it requires your team to stay extremely spaced out. If you don't, your team will just keep getting chipped and having their shield cooldowns reset whenever anyone nearby pokes their head out. With how many abilities require relatively close proximity, this just doesn't feel great. It's extremely powerful, and extremely annoying. Furthermore, the shocktrain user doesn't have to do anything, or even know that those enemies are present to get this extra damage. It's just free bonus damage and suppression.
I propose this: instead of the arcs being able to jump to anyone within range, I suggest changing them to only jump to a target that's both in range, and within 15 degrees or so of the angle of the original shot (or last arc). Basically, it would be like the shot pierced though the enemy, and the next enemy in line (or at least within 15 degrees of in line). This would maintain the extreme power of shocktrains, but require the user to actively position themselves in ideal angles to try to get a bunch of enemies roughly in line with each other.
Just sitting behind your front line and plinking away would still be equally good against your primary target, but you'd no longer be rewarded with a bunch of free hits against people believe cover that you may not even be aware of. Getting a bunch of crowd control damage and suppression would require to actually do something, and enemies have more options for counterplay when getting hit by it (and also are way more likely to actually be able to see and retaliate against the person they're getting hit by). Getting off to the side of the line of battle would present you with the best opportunities for multiple arcs, but also potentially put you at more risk. You know, actual risk vs. reward.