This is my only complaint about the Erebus (Creation) mapscript. I hate having to research techs I don't want and spend 20 turns microing my stack 'o death across a 1-tile channel just to get at a rival on the same continent. I think Great sages should be able to destroy mountains (maybe great engineers - see Hannibal, Crossing the Alps). Of course, that would require them to move impassible, but that wouldn't be too ridiculous or overpowered.