Encumbreance and carry capability are important in roleplaying games. But it can be handled really differently from detailed and precise where every 0.1 pound counts to rougher systems.
Even though some games could need more detailed encumbreance system I prefer lighter ones.
Bigger is harder to carry than smaller. Golden statue might weight more than big painting but you can put that statue in a bag or packback when you must handle the painting more carefully.
It is not always the weight that matters. I think more abstract encumbreance is better as it leaves space for various types of items.
One good example of good carry capacity is in Lamentations of the Flame Princess. There are three types of items:
- unencumbering. These don't generally affect encumbreance.
- normal. There items count as encumbering items. Every 5 of beyond normal carry capability gives 1 penalty to task rolls.
- heavy. There you don't carry too many.
I also like the concept in Resident Evil games where items take slots from your inventory. Extra slots you can get from special equipment.