Why does it keep getting repeated that additional options would worsen/clutter up the UI??? Please someone explain how that works.

These options will, hopefully, be added to an "Options" page in the game's settings, a page dedicated to changing these options. Not the inventory menu. Not the hotbar. Not the character sheet page. Players will see these options (hopefully either in a drop-down menu, or requiring scrolling down) when they first choose the difficulty when starting the game, and then can (again, OPTIONALLY) return to that dedicated-options-page to make later changes if & whenever they wish.

If a player doesn't wish to mess around with the options, they'll theoretically either never or only once see all of these settings. If a player does want to change the options, they have the ability to at anytime. Win-win.

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In other news, I don't think Larian should have to provide a built-in mod manager. That said, they obviously shouldn't be creating the game with the attitude "eh, modders will fix it." It's fairly standard at this point for games to come with a variety of options (at the very least: different difficulty and accessibility settings). And business-wise, adding options almost strictly expands Larian's consumer base. We should obviously keep arguing for options, and then theoretically Larian would decide which ones are worth it based on difficulty and popularity.