The recent update has been controversial however I think something that would fix a lot of this and also make the game more mythological and fun is to make all siege weapons for each faction available in heroic age and present each faction with a faction specific mythic age siege myth unit, similar to titans except obviously less bulky. The factions with weaker siege, for example Norse, has a minimally better mythic age myth siege unit to balance any differences in strength now that siege has a lot more utility.
I think this idea would be awesome to implement both in a way that promotes balance and mythology.
Let me know what you think and like this if you want it implemented!!!