I feel as if ballistic HE weapons have been left behind as of 0.95.
Comparing the mediums with kinetics of the same class: there are five kinetics (arbalest, heavy autocannon, hypervelocity driver, and heavy needler, and heavy machinegun) yet only three high explosives (heavy mortar, heavy mauler, and assault chaingun). The heavy mortar is most similar to the arbalest; it's cheap (in terms of ordinance points), flux efficient, inaccurate, and tops out at 700 range. Likewise, heavy maulers have a similar role to hypervelocity drivers; 1000 range, decent accuracy, and decent per-shot damage at the cost of being a bit more expensive to mount. From these two comparisons alone, it's clear that there's a missing/unfulfilled niche for medium HE. None of the current vanilla options can range match with the heavy autocannons at 800 range, and there's a gap between the 7 OP of the mortar and the 12 OP of the mauler.
In addition, non-large HE ballistics are inferior at cracking armor compared to energy weapons of similar size. The hardest hitting medium HE, the mauler, does 200 damage per shot which translates to 400 damage vs. armor. Discounting the mining blaster, the hardest hitting medium energy would be the heavy blaster, which punches for 500 energy damage per shot. As a more extreme example, the antimatter blaster is better at cracking armor than every single HE ballistic save for the hellbore cannon.
Proposal: The addition of one or two small/medium HE ballistic weapons that fill these above missing roles.