I really like systems that allow the amount of things you are carrying to affect your overall movement speed. It’s just natural. Skyrim did this, although rather sloppily. A game that I felt had a phenomenal system is Dragon’s Dogma. In DD, both character physique and carried items affected movement. Since we don’t know yet how much character customization we will get, I’ll focus this on carried items. All items in DD had a specified weight, but I honestly rarely paid much attention to the numbers (more on why later, just keep reading). As you filled your pack with more and more stuff, you hit different encumbrance levels, and you moved slower. It started as a small change, but the more you carried the worse it got. You’d walk and sprint slower, and jumping was a lot less effective. The reason I say I rarely looked at the numbers is because I didn’t have to look and say, “oh no if I pick this up I won’t be able to run at all”. I knew I was getting encumbered by how fast I moved and how far I jumped. And I’d then offload stuff I didn’t think I’d need for my journey. It was a simple, intuitive and natural mechanic. It just made sense. I don’t know if you guys are looking into a system like this, but if so, please do it right.
I like these systems, but they can be a pain for players who mine huge areas at a time, since they only go back when their bags are completely full. Not saying that’s a good enough reason to not have the system, but I know it will be mentioned. I personally would love it if we had an encumbrance system that also allowed us to load up pack animals that could not be totally over encumbered, and only slowed down a bit when full. I don 't know if I’m describing this as clearly as I want, but a fully encumbered mule should still be as fast as a typical player’s walking pace, but not faster than sprinting.
I have never liked the systems that once you hit the encumbrance threshold you would instantly be penalised. Like a system where you gradually become restricted in walking speed, running speed and jumping.
The idea of having mule type animals is a great idea for those who like to dig and delve @Havok40k.
This type of use would allow traders to roam from world to world selling their goods like the caravans in Fallout to add variety to just stationary shops😊