Seriously, if you want to play with the 50% rule, or anything similar, you have my blessing. You can even do so in a tournament if you wish, and your opponent agrees - quite happy with that too. However, if anyone _asks_ me during such a game, the answer will always be 'play the rules as written.'
The Evo rules system had several objectives, chief among them;
1. Provide a rules system that could be used across multiple genres.
2. Provide a 'hefty' wargame with many tactical options, rather than the lightweight rules often seen in similar packages. Basically, provide what most people would recognise as a 'proper' wargame, not a glorified boardgame.
3. Do all of this on two sides of A3, in a manner that eradicates as much potential argument between players as possible.
This, I believe, we have accomplished. Now, if players want to add their own rules and units, I think that is great! You may violate one of the points given above in doing so, but then all you need to worry about is how you play the game in your own group (we had to worry about how it would play across the world

).