NOTE: the point of this post is to describe the process for how I identified a problem from player feedback, and implemented a solution that maintained my desired gameplay elements while improving new player experience
The #1 point of frustration from playtesters for my game has been that it isn't immediately clear what players are allowed to do when. Players would want to do certain actions, like moving or purchasing units, and would repeatedly get "Requires [attack/administration] phase" messages.
Once players were able to internalize the game rules (2-3 hours of gameplay usually), the phase system felt natural and players enjoyed the game. So to me (and the Indie Games Clinic folks who helped me with this), that indicated the rules didn't need to be changed, but the affordances of the UI did.
(Not pictured) In the old system, players would select units to expend global action points that were shared amongst all units. Units can move together, but only if you realize you could select multiple units. You could not undo. You also had to count the distance between territories in your head, and the path indicator would only show up once you clicked somewhere.
(Pictured) Gameplay rules identical. Now, you select territories instead of units, because that is the type of action system I intended for. When you select a territory, a filter applies to show you where you can/cannot move. The path indicator displays on hover instead of click. And now you can move units forwards/backwards and arrange as necessary, as if this were an actual tabletop game, until you confirm the action and spend the points.
I have yet to test this on playtesters, as I am in the middle of a major UI overhaul and many of the other systems are broken currently. Overall, I think this is a step in a better direction and I'm excited I do not need to change the rules, because they work exactly as I wanted for experienced players.