Looking at the gameplay video again. There are a couple of stills of Arthur carrying weapons or selecting them from his horse. Rather than the never-ending inventory of GTA/RDR could it be possible that we are looking at having to select the right tools for the job?
There are a couple of examples of Arthur walking down the street with a rifle over his shoulder, a shotgun in hand and his revolver holstered. There is also a still of him selecting his rifle from his horse. Could your loadout selection be crucial in how you play the game? For example if you've decided to bring the rolling block rifle with you and you end up in a bar fight you're going to have a bad time.