Acceleration

Pollution/revolution mechanic could allow for a sort of trade-off, i.e. the player can develop really fast but in this case deferred effects on enivronment and society arise. So the player would plan when to "accelerate" and how to deal with consequences... It may feel like a driving simulator.

Specialists

I think most of the population should be specialists of some kind, at least after urbanization. Currently most ppl are farmers/miners and its strange and boring.

Among specialist effects there may be % change to yields, e.g. each enigneer provides +10% to production. This would lead to city specialization what civ5 lacks.

Sieges

cities should not heal if starving
maybe lose some hp per turn

land units should block nearby terrain from working just like sea units

No starvation in Civ Rev

Bought Civ Rev for my phone today.

Very interesting, theres no starvation.
Really, why to have it if cities only grow, 99.99% of the time.

As for me i always thought it would be cool to lay a siege to actually starve a city to the point it can be taken by assault (its defense ability should drop accordingly).