Is that really a necessary response? If something is not worth caring about to you, that doesn't mean it's the same for everyone.
2) it's already implemented
Since when has that been a reason not to change something (particularly in this game).
3) I can't see how removing one option would do anything except create confusion
Can you explain how exactly it would add confusion? I'm simply talking about removing a redundant step, so that when you select "New Game" it simply starts a new game and moves you to character creation, rather than prompting you with "Singleplayer" and "Multiplayer" buttons - buttons which seem redundant because drop-in/out co-op is available regardless of which button you press.
See, there are going to be players out there looking at those single/multiplayer prompts and thinking
"Uh.. well, I'm starting off singleplayer but I might want my friend to join me later.. but I might not. Am I locking myself into a choice by choosing one of these now? I better go ask on the forums..". That's "confusion". It also addresses your "who cares" question.
4) There will almost certainly be additional options to join games, like for LAN and direct IP connection, so differences are a possibility.
That wouldn't matter, as it's still drop in/out co-op and the process from the game creator's side is the still same.
