About Allegiance: I've been thinking:
I wnat to stop it from happening once nationalism has been researched. Also, I am thinking that maybe a 'fanatic' promotion might also provide this effect.
Now then, as for amries switching sides in principal. Armies were rarely slaughtered down to the last man, unless they were meant to be symbolic. Soldiers rarely defected, but they did sometimes surrender, and some, if their loyalty was enough in question, might offer their services as mercenaries, or they might be impressed into service, this happened often on ships in the Age of Sail. Of course some units should not be able to do this, UUs being such units, so I will have to make it so they do not switch sides.
In modern day, when armies surrender, they are taken as PoWs, and returned for a fee or after the war is done. Perhaps after nationalism for each army you lose you gain a shield in some random city? Probably too complicated, so I doubt I will implement it, but it is a possibility.
Dale's Combat mod to the best of my knowledge is slightly bugged, no longer supported, but the AI understands it fine. I am going to test it thoroughly for bugs long before I even start merging it, and only if it is bug free will I merge it.
To anyone who is willing, I could use testers to help me with this, so if you can manage to pull yourself away from RFC for a few moments each day (courage my friends

) could you try the Dale's Combat mod and Report back to me? Frankly, I am willing to rebuild the mod from the ground up if I can and have to, because combined arms attack is something I feel the Civ series has been greatly lacking.