The Mjolnir Cannon has a very nice weapon sprite, and the weapon's description in the Codex makes the gun sound absolutely terrifying. It's also the only ballistic weapon that deals energy damage (thermal pulse cannon not included), so it gives low- and medium-tech ships all kinds of tactical considerations normally reserved for high tech ships.
Unfortunately, the Mjolnir consistently underperforms relative to other large ballistic weapons. Storm needlers and gauss cannons are much better for taking out shields, while hellebores and HAGs outclass it as an anti-armor weapon. Any ships with large ballistic mounts either have enough weapon slots to mount both kinetic and high-explosive weapons at once (Onslaught, Conquest) or can't satisfy the cannon's massive flux requirements (Dominator).
The end result is a very cool weapon that just begs to be used, but is so inefficient that mounting one on your ship just isn't worth it. Am I missing something, or does the Mjolnir need some significant buffing to make it combat-ready?