Really "straight-firing lightning gun" should sell you on this.

The Engineer was seen as less than desirable, so Firefall devs are cleaning him up - his mobility and primary weapon are being tweaked, with a new lightning gun that ramps damage up the more successive hits on a single target, and his gadgets are being improved. His new mini-turrets and instant force fields give him more utility without sacrificing the speed he needs. For more data on the changes and the intent behind, there's a pair of blog posts on the site that cover it.