AFAIK, armour only affected your weight/movement in Apocalypse.
Three years later. Now I am probably the most infamous necromancer of the forums.
Still, I would like to say that:
Armours in OpenXCom can modify all soldier stats, both ways.This means that armour can have Weight, and even a negative Weight (if it's powered, has anti-grav repulsors etc.). It can also improve Accuracy, give or take TUs, or even modify Psi Strength. The game doesn't use this feature, as the original didn't, but it works perfectly well and is available for modding.