It's probably comes down to what one wants from an RPG - for me the fact that players breeze through BG1&2 with a single character is a sign of the system being fundamentally broken. It is afterall a party RPG with a class system designed to limited what each character can individually do. If single character can do it all, IMO it breaks what the game is about. And to counter argument: "what the problem if you choose how to play it?" - in BG1&2 I usually find 2 or 3 characters being constantly useful, while others (like spellcasters) usually hang back and do little to nothing, and then contribute only to the most useful encounters. That's not something I felt though in modern RPGs (be it PoEs, D:OS1&2 or Kingmaker). I suppose it all comes down to me wanting to play full party micromanagement game, and I want it to be as tight and tailor-made experience as possible. I am selfish like that.
Completely agree with this. I feel exactly the same way.