In the TW3 most things are hidden until you need them. Buffs/debuffs, combat log, combat wheel, enemy name plates, horse stamina and fear.. all of this stuff is already contextual and only appears when engaged. The persistent elements on screen are the health bar, stamina, minimap, usable items, current quest, time of day, and the controls. The first 3 are also persistent in RDR's UI, so I'll assume I don't need to justify those. For whats left:
- The items are there because its extremely nice to know which, of the many, items you have equipped in those quick slots and in what quantity. This isnt something you only want appearing in combat because these items are not strictly for in combat use. Witcher is also a game about being prepared and being able to see at a glance what I have before approaching any encounter is useful. RDR has consumables too, in order to use them you must pause the game to invoke a menu and fumble through the inventory to use an item. They saved screen space but actually accessing and using that stuff is far more cumbersome in comparison.
- Time of day seems like it should also be pretty self explanatory. Time of Day has some effect on quests, monsters, and npcs. So if I'm out exploring and I stumble on a ruin inhabited by Werewolves... if would be nice to know if I'm an hour from midnight when they all become super powered.
- Current quest. In the Witcher you may have a dozen(d) different quests in your journal at once, you accept a quest and then get around to doing it pretty much whenever you feel like it. In RDR you can only be on a single quest at a time and there is rarely any reason to deviate when you are in a "quest state" since failure means having to replay the mission over.
- Controls. These are obviously training wheels. Luckily, just like real training wheels, you can easily remove them as soon as you want. Presumably, the same is true about any of these UI elements. If you dont agree that seeing the items is useful, then you can play to your preference. The modular nature of TW3's ui is another huge advantage I'm happy to have.