If all you want is not-EM/Therm, just scratch off the Rokh and Scorp for being inferior to the Raven, and the Mega for being a Thermal powerhouse. Raven, Domi, and Maelstrom will all do you fine. Assuming you have T2 drone skills, you'd probably do best with a Domi and sentries, since you're already an armor tanker.

Hi.

I currently have an Amarr Abaddon and Apocalypse who both mission run. And my aim with these is simply to get a good fitted set of battleships that can do level 4s.

Due to Amarrian damage type restrictions I would like to get another ship that isn't Amarr for level 4 mission running.

I am looking to one of the following: Rokh, Scorpion, Raven, Dominix, Megatharon or a Maelstrom.

I am simply wondering which would be best for simply dealing a better damage type different to EM/Thermic so I don't have to spend twice as long in Angel missions.

Overall the Mach kills level 4s better than most anything else, since it has selectable damage types, more DPS than the missile boats, and can use speed to tank and control ranges easily. Angel Extravaganza IV can be run all the way through the bonus room in under 50 minutes. but it takes good Gallente and Minmatar BS skills. For you as a current Amarr BS flyer, that's a load of skills to acquire (including large projectiles). For the domi player that posted, you've got a somewhat shorter train to get there. and of course, expect to spend a good billion to billion and a half ISK to buy and fit one well. that's the expensive option.

Another possibility is the Rattlesnake. Good drones, good missiles, variable damage, and a good tank. also expensive.

the Domi will get a slight push with Hybrid re-balancing that makes it a better ship, rails get a damage boost.