The original supcom Mavor was crazy.... it would basically target the enemy ACUs as soon as it was built and would head-shot them from however many miles away it was
The game enders now are considerably weaker. The Paragon is good.... but Aeon hasn't got the build power to use it and, in the games I have seen, it's more effective just to get a Salvation first rather than a Salvation after a paragon. Also, the Salvation is ridiculously good and will destroyer any base. Similarly, the Seraphim nuke is strong and will destroy any base as soon as burns through all the SMDs the person has stock piled... so it takes longer than the Salvation. The Scathis is good, but has a lower DPS so is worse than the XP nuke/Salvation. The Mavor is just kind of crappy now and easily the weakest of the bunch.
The tech 3 heavy arties used to be a lot less, I think, but were made more expensive in FA to prevent mavors/scathis/salvation from becoming useless... after all, why build a mavor if dukes are more efficient at projecting the fire power?
Having established that context, I would like to see a reduction in the cost of tech 3 heavy arty. They are all around 90k mass and I wouldn't mind it being about half that. To balance, Mavor and Scathis should probably be reduced in cost by about a third... and increased DPS about a third... to a total of 200,000 mass cost and 2000 DPS (from 300,000 and 1500). I'd leave Seraphim XP nuke and the Aeon Salvation alone because they are both very good.... ad because Seraphim/Aeon have much better tech 3 heavy arties than Cybran and UEF. Serpahim's actually looks the best with it's combination of range/DPS/cost/blast redius with Aeon a close second. Also, I doubt it will be OP because, in the present game, bomber snipes (torp or strat) are pretty much the only thing we see for late-game endings.
So, summary of my idea:
Mavor/Scathis: -33% cost, +33% DPS
All T3 heavy arty: -50% cost