@Vendetta Very interesting. I also always have disliked that you could block an advance by just putting one infantry in the territory. On the smaller maps this is not a big deal, but on the bigger ones it makes advancements very slow, so then it would be very interesting to have a sort of blitz ability.
Have you ever heard of Global War 1936? There they also have an interesting blitz rule. If I can recall correctly, if the terrain was plain and the combat lasted for three rounds or less, the attacker can blitz with tanks, mechanized infantry, fighters and/or tactical bombers that still have remaining movement and attack another territory. Makes a theater like the Eastern Front much more interesting.
Currently, you need some XML hackery to get this to work. You'd need to add two CM and NCM phases for every player - a regular CM phase, then a NCM phase to reset movement, then another CM phase for the blitzes, and one more NCM phase for regular non-combat movement. Then, use triggers to prevent movement of non-blitz units in the second CM phase (e.g. infantry, artillery, etc.). The blitz conditions need to be player-enforced though.
Expanding the TripleA engine to better support such a "blitz" feature is definitely possible but requires some work. I currently don't have time for this but maybe in the future some developer will tackle this.