One of the fundamental problems with the combat in X-Com and in Xenonauts is with the shooting - all it does is wound or kill units. This may sound trite, but it is an issue in that most weapons can fire in both single shot mode or burst fire mode.
In the current incarnation, assuming that you have enough APs to take a burst shot, you should always do that. It provides the highest average damage per AP spent. This doesn't really give you much in the way of tactical options. It's just simple maths as to what fire mode gives the best bang for your APs.
It was suggested a month or two ago that we look at the suppression system from JA1.13 for inspiration. Naturally I've been far too busy to actually do that, but the idea of suppression has grown on me enormously over the last few weeks as it provides an obvious solution to the problem above. With suppression implemented, we can have burst fire causing lots of suppression but not actually doing that much damage, while single aimed shots are much more effective at causing damage but don't cause anywhere near as much suppression.
It also means we can change the battlefield roles of some weapons a bit - for example, machineguns and the Ferret .50cal. In both cases it's been difficult to balance these to be effective but not overpowered. Giving them very high suppression but perhaps no more actual damage than the sniper rifles would make them useful support weapons but not overpowered in effectiveness.
Suppression would be something that is built up with each shot the affects the unit, draining the unit's APs first from his reserves (used for reaction fire) and then from the next turn. With enough units shooting at the same target, it would be entirely possible to pin them in place.
Initially I was going to suggest we tied this into morale, but on reflection I don't think that's a good idea. I don't think a soldier who is pinned in position by enemy fire is directly more frightened than one that is not, rather they are keeping their heads down to avoid getting shot. Perhaps we can add a small morale penalty for getting suppressed or pinned, but I don't think the suppression score should use the morale value.
Rather, I think each unit should have a Suppression score that is based on his Bravery stat, giving it a common root with Morale but a shared value. This will start at the soldier's Bravery value, which is anything from 50 upwards (as the lowest starting value for any soldier attribute is 50).
Each weapon fire mode will have a "suppression damage" value, and when a soldier fires a weapon at a target (irrespective of whether they hit it) the suppression damage will be applied to the target's Suppression score. This is affected by armour as usual, so if the unit has powerful armour it will not be suppressed by firing weak weapons at it.
Once Suppression reaches 0, any extra supression damage recieved is first deducted from the unit's AP reserves for the current turn (down to 0) and then from the AP in the following terms (again down to 0). Further suppression is wasted. Maybe we'll have a symbol appearing above the head of the unit to show it has been suppressed?
The Suppression score should regenerate a certain amount each turn, perhaps something like 20. That means three turns without being fired at would return any unit to their full Suppression "shield".
Anyone got any thoughts, suggestions or improvements?