Mesons would be great for this, as they should be able to penetrate GU armor and thus only roll against HP. Particularly if they are reworked to gain +damage from one of their techs (they really, really need a buff!!) this could be very effective.
Microwaves might be interesting but they already have a good niche in a JP defense role or a FAC role so they do not need the help as urgently.
Exactly this. In fact, Mesons might make that roll
already. Has anyone tried it? It would also be very interesting if some percentage of the baseline meson armor penetration tech-line (that governs how likely a Meson is to penetrate all layers of armor before decaying and applying its damage point) is also applied to fortification/terrain bonuses. Even after the space/ground scale adjustment, one point of damage isn't a lot; but if mesons had some ability to reach out and touch dug-in troops in rough terrain then that'd go a long way towards giving them a secondary role and give you a lower-collateral option for effective close support of troops in contact. Just based on HP-vs-damage, heavier units would be likely to survive a hit, but not having to unleash big-bore beam weapons just to penetrate the armor in the first place would go a long way towards reducing collateral damage.