Distance was a factor in casting costs in Mo. It ranged from a .5 to 2.5 multiplier. Hero's on the field had no such multiplier and depended purely on their own mana reserves. Heros in your citadel added half their skill to your own.
In deference to leeboy26 , if you like the randomness, that's fine. I personally edited the game to balance out many of the random factors. MoM was and is very detailed game. (Thankfully it always had in game help to walk you through 99% of everything. If one could be bothered to read it.) That's what I like about. The Age of Wonder series probably is the closest mirror to Master of Magic, but they don't have half the detail. Game play or interface wise.
You can easily get by with ignoring 75% of the content of MoM, if you really wanted to and didn't mind nasty surprises. You'd just miss out on 75% of the game, that you full price for.
I've been accused of hacking more then once over the years simple because I read the manual, and was one of 2% of the player-base that knew how the game worked. Then, shock and horror, actually applied what I read. I look forward to FE with slavish and fan-boy glee simply because of the likenesses to Master of Magic.
----
[soap-box]
My apologies to Stardock if they take offense, but it seems to me as time marches on games get stupidly simple for all the "advances in technology". I don't mean easier to grasp, I mean stupid. 'Frozen Bubbles' ( http://www.frozen-bubble.org/ ) is easy to grasp and hypnotic fun! Modern games seem to be based are shiny things and avoiding having to do that ...re.... read ..."reading thing". In fact, avoiding having to do anything like actual thought or longtrem planning. Just short-term or 3rd grade math if someone can be bothered to even do that. Then press 'fire' or 'A' for the next endorphin hit.
If YouTube is anything to go by the literacy level, comprehension level, and just general attention span of the average gamer seems to be around the 3rd grade level. May I never speak such a snobbish thing again, but still, It's true! 
[/soap-box]