I'd rather that my rivnak or drifter have the ability to carry things on their own, sort of as if they could act as containers holding their own inventory. After all, shouldn't a character's pet be able to help carry extra things that would overload the owner?
I like this idea. I think when you mount a mount, that your STR goes up so you can travel longer, carry more, etc.
Having a saddle for a Rivnak and something else for a Drifter would be great. The saddle could have a carry bag in it.
Also wondering if you could get carts, carriages, wagons, etc. In the future.