My first attempt at a mod, I would really appreciate feedback on the mod and the code and if anyone wants to try it out (see Releases section in Github).
https://github.com/red-moss2/ArmorAffectsMovement
The overall plan for the mod is to make the weight of your equipped armor and weapons have an effect on movement speed, climbing and jumping, factoring in the player's strength. There is a setting you can adjust to make this overall effect weaker or stronger.
This means that completely tanked out daedric chars will basically not be able to move as fast or climb effectively, whereas leather wearing dagger types can move freely and jump and climb to outwit their enemies. Heavily armored characters will need to improve their speed by magical means if they want to have good manoeuvrability, thus creating more space for hybrid "magic tank" playstyle.
Horse and cart speed is not affected (as far as my testing goes) nor is overall encumbrance factored in, because that would just be tedious for getting about more generally.
Right now only walk and run speed is implemented, I am going to do jump height then look into modifying the climbing failure rates dependent on load. I also want to make it so that sprinting in heavy armor confers a bigger endurance penalty, and have an option to boost jump heights a bit as a baseline.
Here's a chart of the default settings to give you an idea of how speed is affected as a function of strength and weight. For example, a player of 50 strength with about 50kg of equipment will move at 70% of their usual speed. Values over 1 in this sheet are clamped to 1 in the mod.
