Reducing flying units' movement on mountains

[aquamarin]

Flying units are often very useful in any Fire Emblem game due to their terrain-defying mounted movement.

Wouldn't it make "sense" to hinder their movement on mountains though? Unless you are talking about some pathetically low hills, the fliers would have to fly vertically as well as horizontally.

Of course, nothing in Fire Emblem has to make "sense" with thrones that let people dodge more and arrows that penetrate walls. However, this change also makes sense balance-wise, since flying is stupidly good in FE.

Would be interesting to see someone implement this in a patch.

[Psych]

You wouldn't even need a patch for this though, you can change terrain movement costs in nightmare

[Celice]

Would there also be avoid bonuses/losses for trying to navigate the steep cliffsides?