I know I'm a noob and this has already been mentioned several times... but not recently! Tireless March is a great spell (maybe up its mana upkeep to 2) but having multiple heroes with it in one army should not give cumulative move bonuses. This causes realm defense to degenerate into shuffling one multi-hero army back and forth, which is less "fun" both strategically (as you don't have to make real choices about having multiple armies) and tactically (as you fight essentially the same battle (i.e. with the same army) over and over again).
It's a rather unique spell, I guess, so I understand if it may actually take some monkeying around in the code (rather than XML) to accomplish this, but it really should be done. I understand this will almost certainly get put off until 1.1 (or later) but it still needs fixing.
Also, it shouldn't provide any bonus in tactical combat (thematically or balance-wise, IMO), but as the "moves" statistic is shared I can understand that it may be cleaner, code-wise, to not put in something to separate this out.