I have totally no idea how far along the megacity feature is... but I have to admit I am a bit disappointed that it won't be there for launch as at least one of the advertised advantages (having to build only one nexus) won't help that much if it comes much later. Anyway, dev resources are always scarce.
SO, if you are open to ideas - I have always imagined that megacities would be like having a way bigger grid. But I can only guess this created a ton of edge cases and very special situations. Will you have to PERMANENTLY fuse 4 lands to a megacity? Otherwise what happens if ownership of one changes? And so on.
The idea:
Could you maybe use a "megacities light" concept instead that is way easier to implement. Like the land that is currently being played only checks for adjacency. I.e. check whether there is a land owned by you with a higher efficiency bonus directly next to this land -> use that one.
- if you want to send resources: if the target is adjacent, it works instantly.
- check for required buildings on adjacent plots owned by you, and display build options accordingly
So the overall gameplay would not look or feel different than playing a single plot, but you would just have extra options available while you own additional land nearby.
Maybe with a visual cue to highlight that you get bonuses.






