I believe removing valour for all HA and HX will make them fight(die) earlier, instead of delaying.
On some maps, motf is clearly in cav advantages though. And making it spawn earlier will actually, sometimes, give the win to the lone lancer/HX, wich would be stupid. But at least, fights will go in one direction, so why not.
If you could make the spawning place of the motf related to the current positions of the two teams, then that would solve the problem. For example, always make the motf spawn in the middle of the shortest distance between two players of different team. That way, no one is at a disadvantage, and the real fighting will begin sooner.
Of course, such a thing is near to impossible to implement, probably.
Edit : OR i belive the motf place is map dependant, and always the same on one map. So... if people could know where it is, even before it has spawned, then it could be interesting. That way, infantry would know wich place to go to right at the beginning. Of course, veterans players do know where it spawns, but even by playing a full week, if there's real battles, and no motf, you don't know where they usually spawn.
I like that last idea the best :
Force the appearance of the motf, and show where it will pop up, before it actually does.