Paragon is the only true game-ending device. Build as many Salvations as you need.
You're better off building T3 arty then building Mavor or Scathis. You can put increasing amounts of pressure on your opponents. Three dukes actually do more damage/second (1650 to 1500) than a Mavor, and cost less 270k to 299k.
Scathis has high damage and good range but you wont be precise with it.
Yolona Oss is awesome, but also stupid. If you as Seraphim built a YO and your opponent as Aeon built a Paragon, you are screwed. He builds 10 SMD before you can deplete is anti-nuke reserves and then he builds Salvations and there is nothing you can do.
This happened to me yesterday in an FFA. I lost as Seraphim against an Aeon opponent with a Paragon. My YO couldnt get enough nukes in the air quickly enough before he had 2 Salvations and 15 GCs hitting me.
There should not be a hard-counter to a game-ender. I say buff the Mavor, Scathis and YO.
Maybe YO should have every SMD in range fire a missile at it.It wouldnt matter how many SMD you build as each one would fire an anti-nuke at the YO each time. Then you could last for at least 7 shots probably a few more as the missiles rebuild, but you could not hold it off indefinitely. Your base would still hold out longer than against Salvations or Scathis/Mavor.