I added Energy Bolt simply because it fit the concept of the build, thanks to overheat. Personally, I prefer Earthquake as a skill, and if you wanted to use that instead, all the power to you. I probably would too, but I don’t always build with my preferences in mind. 
If you like fire ball, go for it. I find it a bit of a wonky skill that requires you to waste time hitting it around the field. Also, the skills I chose in its stead deal duration damage, which combo well with Hell Breath, Psychic Pressure, and Flesh Hoop. Also, because the duration damage skills tend to sit in place for a while, they work really well with Swap. The goal is to stack damage from several skills at once.
If you want a build that works well with Alchemist, you could drop Necromancer for it. This would lower your damage output, but that’s part of the risk when taking any of the crafting classes. I’m sure future class ranks will make up for the damage loss. The build would still be viable without Necromancer. 
