I'd like to see at least some minor drawbacks to armor for a number of reasons, the two easiest to name being: This would give us more real, serious strategic choices and fewer no-brainers (e.g. more armor is always better), and because we are used to this from most other strategy / RPG game genres.
To facilitate this, I would like to see the basic default movement rate for human-sized bipeds to be greater than 1 (for example: 3 or 4), and have all movement scaled accordingly (e.g. tiles would represent a space four times smaller, for those who cared, but otherwise no real difference would be felt). "Light armor" should reduce movement by 1, medium by 2, and heavy by 3 -- as well as create the standard defense or dexterity limitations we are familiar with.