Quite a few of us participated in the epic Mercenaries vs. BRD battle this evening. While it was an interesting experience, I think everyone agrees that battles lasting 1h45m should be avoided. The reason the battle took so long was because it was beneficial for both sides to camp, so both sides just kept camping waiting for the other side to make a move. When battles last this long, people start missing appointments, it postpones other battles messing with the schedule, and in general it just becomes very drawn out. With bigger armies, the battles will only get longer.
I propose a maximum time limit of 55 minutes for Strategus battles. At the end of the 55 minutes, the attack is simply halted. Both armies remain in place with all their unused troops and gear intact. If the attacker wants to continue the assault, they must attack again.