Can I just ask why the yolona costs more than the mavor and the... damn what was the other game ender?
The Ylona Oss costs less...
You need 2 missiles for each Ylona nuke, the anti-missiles take 4 minutes to build, so you need 8 SMDs to hold the Ylona off indefinitely.
While this is a hard thing to do, it is not impossible, certainly not because 8 SMDs and their first missiles cost 88800 mass to build, leaving you with the mass of 47 Strategic bombers more than the enemy has when you fill in this potential mass expenditure. All in all, I don't think the Ylona oss has become too cheap.
On the subject of having it
cheaper than the Mavor and the Salvation. All Game enders had a price reduction of 25% (the Ylona was cheaper before the change) and all have the ability to destroy an enemy base, but all can easily be destroyed (if found!) because of the huge amount of mass they still cost. As a result, it is almost impossible to compare them with one another, more so because we haven't got a single replay of anyone in action, let alone while players were evenly matched.
Because of this, the only thing we can actually conclude, is that the old mavor is too expensive for Winter's Duel (Lu Xun tried that as a joke but his opponent recovered and managed to win)