Back to one of Chad's original concerns with Umenzi, the hex/bless spam or spell-spam, to me the solution on that isn't terrain objectives. I always work backwards from the desired effect, which seems to be preventing spell-spam by Umenzi, limiting them to a 'reasonable' amount of hexes & blesses.
If that's the case, I'd suggest start with determining what number you consider reasonable. Then I think the simplest way to do it would be to just limit the amount of hexes/blesses to that number per spellcaster unit.
Kevin raises a point that enemies who hang back will benefit from not having additional spells cast on them once that cap is hit. That is true, but usually if an enemy is hanging back its because they're shooting, so those Hexes will probably come off. The bigger point though is that if Shamans are costed at getting a "reasonable" number of spells, then not getting more than that because the enemy hangs back doesn't make the Shamans less good that than their points say they should be. For example, if the idea is that a Shaman unit should have 4 spells happen before the lines hit (and are priced accordingly), and he hangs back giving you a 5th turn, then you still got your money's worth out of the unit.
This completely mirrors my thoughts on the problem.
I don't think you should cap spells unless you are going to cap archers, too. AFAIK archers are priced with a certain number of attacks in mind, and so for that matter are javelins.
This is where the difference between the Umenzi Spells and the archers becomes apparent. The majority of ranged attacks start the battle out of range - so counting how many shots they get works from when the armies are within that range. If there are ranged attacks that can hit the Umenzi from turn 1 then the Umenzi player is making a fair trade of taking more hits but buffing more units. When the opposing army has no ranged attacks/ all ranged units are out of range and the Umenzi are delaying, they are essentially getting "free" buffs and slowing the game down.
Heck, if there is a cap on the maximum number of spells the Umenzi can have active why not let them cast them before the battle starts? That way no one has to wait for the Umenzi to "set up".
Personally I like Chad's initial suggestion for altering the follow rule. As for stacking weenies - I have no problems with it. The more weenies getting stacked to stop any given unit, the more points that are essentially getting thrown away.