As someone that loves the prospects of this game, i am also concerned with mechanic decisions that could make for very unfair disadvantages for certain styles of play. And while this is mostly in terms of the multiplayer aspect, it should also be considered for the singleplayer game.
For one example, lets take religion, which was lightly touched upon as a concept mentioned in passing in one of the livestreams.
My ideas on this is that you should not be handicapped for choosing to adopt a play style that invests more into a secular, or even a nonreligious route, for example if choosing to invest into temples and priests and whatnot gives you some advantage that cannot be balanced with someone that chooses a nonreligious or secular style of play, then that is a bad game design.
My idea for bypassing this would be something like a branching tech tree in concept. You choose to invest in religion, and you will not be able to have the benefits that the other decisions would give.
Maybe not a flat-out “choose this, that is gone”, maybe just something like “you invest in this, now you can invest less in that,” or “now you can invest less in technology” Whatever benefits those would be are up to the developers.
Another example would be the diplomacy vs military axis.
Choosing to be a diplomatic should not put you at such an unfair disadvantage that you would be run over by someone playing militaristically.
An example of balance here would be the ability to bring in troops from other factions to drive off invaders, like hiring goblins or kobolds to patrol your borders through trade and diplomacy if you have invested enough into that.
The main point is that aside from the obvious disadvantage of not playing the game very well, you should not be put in a radical disadvantage by simply not wanting to adhere to a determined ideology, or not wanting to be a huge military might.
An example of this in effect is Age of Empires, monks could be a pain in the ass to deal with in big numbers if you did not also have them or used pure military might to overwhelm the army protecting the monks, that forces your hand in deciding how to play, which is bad for a sandbox game like Stonehearth.
I could come up with some more examples, but i would rather hear if anyone else could think of balance issues along these lines, so please pitch in with your ideas for balancing potentially unfair advantages.