My 5 cents
Absolver - yes its really good at what it does but is role is very niche - ironically its best used against its own faction, due to harbingers having shields, usefull against seraphim with t3 mobile shields, limited against uef and absolutely pointless against cybran, making absolver emp would make the unit more versatile against all factions and units, but if not done reservedly could easily become op, I always thought that shield breaker would suit cybran better as they dont use mobile shields.
Czar - best used against asf as mentioned above, but rubbish as air to ground despite having big laser, a small speed buff would make it better to use in both situations but something that big moving quickly could look strange, so hp buff would be prefered as it takes only 25 or less asf to kill it
Spearhead is annoying as hell, most of the annoying units in faf belong to UEF, lower hp would be nice, also consider to prevent fire when moving.
Novax - obviously
Othuum - speed buff would be nice to counter short range, another point for seraphim would be to match mobile shield speed with othuums, come to think of it all of the t2 shields move at different speeds to the main fighting units wich has always bugged me.
Stealth - is brutally effective but rather than changing stealth costs consider making t1 scouts cheaper, not the build time just mass and energy, navy stealth is far more jarring as distances are much greater
I have no thoughts about the mercy its very rarely used, however I have seen it used to devestating effect but I have also seen it acheive absolutely nothing so meh.
same with the paragon very rarely seen maybe 1-100 games and ive also seen people with para get stomped, so if you can get away with making one without being punshed then you probably deserve to win at that point anyway.

