Then you're looking too hard. 50 mana is hardly "hefty",
We're not playing the same game I guess. For the first 25% of the game, I have a hard time making more than 25/turn. 50 is thus at least a 2 turn mana income. That is not going to be used to ensure a victory and clear an area (say fireball or such), but to put something that may well go puff in the next few turns when a monster rampages over it.
The next 25% of the turns, the 50 mana is a full turn production (well, that's still the optimistic view.) ; a good city is producing a pionneer at a rate of 1/two turns, and I should have at least 4 to 6 cities by that time. Pionneers come thus much cheaper... Actually, so much that even when playing Pariden, I sometimes end up using pionneers for outposts.
After that, you usually are already winning, and anyway, most of the map is already under control of somebody. This is the time where monolith really shines : you can afford to pop monoliths, and to do so far from your home. But this is a late game advantage, and as such it should be more powerful than advantages that come into play immediately. In addition, at this stage, you are very likely to go to war, and your far away monoliths cannot be defended. Poping them is thus a double edged advantage.
Still, there is one thing where you are right, and this happens because of another change against which I am fighting: Hero XP splitting. This makes heroes useless spectators (at best) in the fights they are involved in. As a consequence of heroes being now irrelevant, the use of magic is also much less pressing than before and mana that used to be in short supply is now accumulating.
So yes, if XP splitting stays, then monolith is a bit too powerful ; but not that much because by the time you really have enough mana to spend to spread monoliths, the game is already won. If XP splitting is removed, then monolith is ok because your heroes should put a big pressure on your mana pool to force you to make choices.
Yves
