Here's what I would propose: Take the mods out of the rolling process as much as possible. Let the involved parties take care of it.
Rules of Combat:
Combat is engaged when one or more players commit a violent action against one or more other players.
When combat is engaged, roundtable turns will begin among all parties directly involved in the engagement. Turn order is determined by initial rolls whenever combat involves more than two players. The attacking player goes first.
At the beginning of his/her turn the player will make a choice to either: 1) propose an action and a roll, or - 2) dispute any of the actions/rolls which have been proposed by other players since their last turn. If no disputes have been raised since the player's previous turn, his/her previous turn becomes canonicall and can not be disputed.
A dispute will include a reason for the dispute, and can be approved by either a mod or the player whose action is in dispute. A moderator can approve or deny a dispute but a disputed player can only approve the dispute.
If a dispute is approved by either a mod or the player whose action is in dispute, the combat engagement reverts to the point immediately following the last approved turn and it becomes the disputed player's turn again.
Rolls are confirmed in IRC by either a moderator or all players involved in combat.
TL;DR - player-disputable turntable actions. By submitting an action, you approve all previous actions and rolls (check your opponent's rolls in IRC!). The game can proceed without moderator intervention.
One of the major problems with the current battle system is the amount of time it takes to resolve conflicts. This would not fix that issue, and may even make it worse because there will be no framework to end the battle. In fact, it would definitely make it slower, because we automate the rolls now. We can complete 10 battle rolls at once, but rolls would need to happen one at a time under this more free-form system.
I do like the fact that it would give more control over battle strategy though. Currently, you can't really do anything once a battle has started except retreat. We need to find some sort of middle ground between the influence you can have over a battle vs getting it resolved as quickly as possible.
Another thing to consider is the difference in combat. If we are going to do this 20th century powers thing, WW1 and WW2 battles will be very different.
If we were going to use this, we would need a framework for it. It would need to be streamlined to push conflicts through very quickly.
There is also another issue with this. Both players have to be around at the same time to be able to finish a conflict, meaning we could end up with frozen conflicts for days on end, not because the system is slow, but because one or both of the players isn't available.