A few notes:
1. Enemies already only DO get an action if players are within range 20 of them. So if you and I adventure on entirely different sides of the map, then it plays like solo.
2. I should have mentioned before, although it sounds like that really hasn't been encountered yet, that the multiplayer here is entirely preliminary in terms of underlying bugs. The design
is considered pretty much close to final, which is of course what you are complaining about, though.
3. In general, the goal of co-op for me is to have it be "the same game, but I can play it with my wife." In other words, not some special other mode. Having double the number of Exos, or quadruple even, would absolutely wreck the balance of the game in all respects. We'd have to do missions that were twice as big or more, which again would wreck things. So the whole thing with the shared bots is rather a necessity. I understand that some folks may not like that, but I think it's unavoidable.
4. There honestly is a good reason that there are not many multiplayer roguelikes. I feel like we've solved the problem pretty well, insofar as this is an intractable problem in the first place. During combat, having it be so that each action is carefully placed is kind of the point anyhow. But it's only really something that is solved if you have two methodical, tactical-minded people. And the point about there being a point-person causing issues is certainly well taken.
5. That said, if it's not fun for you, then obviously that is a huge problem beyond any platonic ideals of balance.
Here's how the turn stuff currently works: every time a player takes a non-free action, the enemies who are alerted within range X (currently 20) get to take a move. Right now I think it's manhattan distance rather than flood fill, which is probably not the best.
One solution that we thought of prior to the private alpha, that was rejected at the time but which I see hasn't been mentioned here yet, was to have only the player closest to a given enemy give that enemy an action when that player takes an action. The problem we saw with that was having one player stand back and fire while another player stands closer to the enemies and just stands there, granting them no actions and blocking them from taking them.
A solution to that problem would be to make it so that if an attack on a tile is closer than any player, OR the firing player is closer than any other player, the enemy gets a move. That would solve all the exploits I can think of, although this solution is new in my mind so there may still be some.
The other thing we could do, of course, is just say eff the balance and let there be one move per connected player. We could also cap the player count at 2 rather than 4, to prevent this from getting runaway crazy. I'm just not sure this would be feasible with more than 2 players anyhow, in a fun or coordinated fashion. That's probably something we need to do in any case.
If we needed to counterbalance the enemies in this scenario of having two moves per player team when there are two players, we could increase bot ranges by 1 or something. Throw the balance off AGAIN in a different way, so that simply the MP is a different experience. There are surely things we could do to make the balance there interesting, at least.
The other thing we could do is make this a single-player game, if this is just going to wreck impressions of the game or cause buyer's remorse for someone who buys a game to try to play multiplayer and then gets enraged by the implementation.
The other thing we could do is make this a semi-secret unadvertised semi-unsupported feature, where you have to enter a special code to get this to appear, and then that's that. I say semi-unsupported because for a feature like this there's a limit to how much we can support it if it's that hidden and secret. I'd be pretty tempted just to cut the feature when it comes to that, because if a secret feature is interfering with the main game, that's not good.