Overall the rules for brigades breaking (half or more of the units destroyed, shaken or off the table) works really well. It keeps the games moving briskly and makes it very important to keep some reserves! But I was thinking that for some games it might be reasonable for brigades to be able to rally after being broken. The way it would work is for the brigade to withdraw outside small arms range from all enemy units. At the start of the turn the brigade commander (or any other nearby leader) can then make a command roll to rally one of the units in the brigade. If successful the unit is no longer shaken and if that brings the brigade below the break point it is rallied and can act normally (probably spending a few turns doing additional rallies!) If the attempt fails the brigade has to retreat another move. You can make the attempt each turn until you succeed or the brigade retreats off the table.
Our group have experimented a little with things to do with broken brigades, in our evening pointed games we leave all as rules but in our bigger full day scenario games we do allow some rallying and stuff dependent on the game.
I think a lot depends on your scenario or set up. In principle I think it is fine and could work especially well for colonial forces who would in all likelyhood not simply surrender as they'd be massacred. As you rightly point out it would take a long time to get a formerly broken brigade anything like fit for action again. The downside is that you could have games that refuse to die especially if the armies are large and you can easily rotate damaged units out of the line.
Boy, it sure would be nice if we had some grenades, don't you think?
Nice idea, especially with Hobbitmiles consideration for smaller colonial style engagements.
We've used an amalgam of HC rules counting a brigade broken when all units shaken or more than half are destroyed (not counting artillery for either) which works well for smaller 2-3 brigade games with smaller brigades of 2-5 units depending on what you've got or how you want your ORBAT to look. It's meant the games last a bit longer, each brigade is a bit more survivable, and has played well so far
I have had 4 games in the last week or so using various options for brigade morale (Marlburian) and we have settled for this option:
All rules for broken brigades as per Pike & Shotte version of the rules with the following exception; at least one of the units in the brigade must have been destroyed and removed from the table.
It makes brigades slightly tougher to break than normal but doesn't tip the balance too far the other way. Our rationale for this is that the shock of losing a unit in rout, shot to bits or chopped to pieces etc. would be the catalyst for a brigades morale to slide into the area of being broken and thus losing the will to fight on.