Like I said.. I'd love for Steam to just have a built in account management system when you go into the client, add your various accounts, and then games simply query your Steam Account to see if the necessary account is logged in, and then just does it automatically. If not, it askes you to add one.
I don't mind that games require log-ins to accounts... it's completely understandable in my eyes, obviously for MP games.. however it IS annoying that every game has to ask me individually.. especially the Microsoft ones lol.