Hi! Thanks for sharing your thoughts.
If you haven't spotted, the Royal Decrees upgrade provides a mix of positive and negative effects that last the duration of that Queen's lifespan, providing more variation in the kinds of balances the game asks you to find. This is particularly impactful for new hives, but can also shake things up for larger hives depending on the combination of effects (particularly with the increased number of concurrent Queens that the Royal Apprenticeships upgrade allows).
First Queen represents a sustainability milestone rather than the "end" of a game. There's nothing wrong with not finding enjoyment playing beyond that though - every player's subjective experience is different!
I'm not sure that reducing the playspace is of any real value outside of possible challenge scenarios. I've been considering allowing the playspace to expand infinitely, but at this stage, that's lower priority at this compared to other changes I have planned.