Should we ban the Griffin Conservatory and the Hive of Serpents?

What kind of nonsense are you talking about? You take Andra as a starting hero instead of Tazar, and rush on the second week. I don't see any big problems with taking Utopia on the third week, even without free troops.
+ Any Necromancer in the tavern is a bonus.

All of this is relevant and doesn't violate any rules. I don't understand this panic about rushing on the second week; firstly, you still need to find a path to the opponent, and secondly, everything is quite balanced and doesn't involve free wins and angels (but with them, that's where the balance often fails; having about 7 angels on day 124 is quite imbalanced, no Andra can help with that), for every Andra, there will be a Gurney with mass haste.