I think if you have to find additional payoffs then the deck isn't good enough.
Estrids Invocation is potentially really powerful but the pool of things to copy with it isn't very good
- Omen of the Sea is slightly overcosted for legacy
- History of Benalia also slightly overcosted for legacy
- Tymaeret Calls the Dead similarly overcosted
- Sarcomancy too underpowered
etc
If you go the other direction in terms of the mana and try to copy huge expensive haymakers with it (like court of grace or whatever) then it's hard to come up with a build of the deck that makes sense to me
I think the solution might be to go 3c so you can play abundant growth as a cheaper enabler (unfortunately I don't think the deck can be purely UG because there doesn't seem to be good wincons in green but maybe there is some food interation with Trail of Crumbs? Lol I have no idea)