Interesting piece….
We use predominantly home-grown rules so a points-based affair does not happen. The exception is when we have a skirmish based On Barons War, Clash of Steel or similar.
For bigger battles, we design the scenario ourselves and we rely on our understanding of the capabilities of troops under our rulesets to ensure we are making a balanced game. When I say balanced here, I am not referring to equal forces, but forces that will "give a game". This could mean one side grossly outnumbers another; however, the scenario and the aims of the scenario may require such an imbalance in order to provide a balanced game. For example, a strong defensive position may only have a small garrison but will require a large attacking force to enable multiple attacks and so on. On the downside, I don't see a newcomer being able to do that, because we have all been using home grown rules for 20 years, so we know what makes a good game and what won't.
The problem I have with historical games is that they are historical until the first turn. unless you are going to closely follow the real battle, it is not going to be an historical refight. An historic battle is great to see "what if" as you say, but how much do you closely follow the original battle before you try your what if? How do you cater for the god like view of the table, and the benefit of hindsight and study of the battle in question? To my mind, historical battles won't be balanced because there are way too many variables.
At the end of the day, a balanced game is one where every player has an equal amount of fun, that is the balance I like to achieve.