All you need is an earth spell, depending on the type of the chokepoint. Shrug.
It usually takes a minimum of 2-3 applications of -land to carve your way through a hill barrier, assuming you have an earth magic champion (It would be nice to think no spell school or build is mandatory). 150 mana is not a paltry sum in the early game, when your mana rate might be +3 a turn. It will require you waiting around to either stockpile mana, or building a spam stack of disposable units to punch through a higher level enemy barrier or city, if that is an option.
Either way, it can effectively bring the game to a stop, which is a bad thing in FE. The AI continues to suck up resources and expand, getting more powerful, while your champs twiddle their thumbs without anything to do. The game suffers when you are not adventuring, as do your chances of victory on higher difficulty levels.
From my .85/86 games, it seems the terrain generation has changed to naturally create insular pockets of territory that can more easily be choked off. I recognize the Fall From Heaven influence here. It creates interesting opportunities for strategy later on, which I like, and slows down player expansion which is probably good, but it can occasionally be problematic in the early game. You can sometimes find yourself bottled up in a map with nothing to do but wait the situation out.
