I think the master key should only be unlockable option and not available from the start (unlock when finish a playthrough, or after X hours of gameplay or something).
Partly because beginners can get so lost and end up in way too dangerous places (given how little guidance the game gives to people where to go)
Screw that, that is the sort of 'hand-holding' that this game does not need added.
But also because there are so many good weapons, shields and other items right at the start of the game (using master key to drakes) that you spoil the discovery of the game. For example, there are a huge amount of regular weapons in the game, but with master key you can get a weapon right at the beginning that makes all regular weapons pale in comparison (until you upgrade them much later on).
If people want to do a speed-item run, why stop them? One of the great things about this game is that it allows you to play how you want to play, not how the creators tell you to play.
Too many games put you on rails and say 'here, play this way - and only this way, and within OUR vision' and any attempt to deviate from that is a smack in the face.
Dark Souls lets you run around however you want. Want to do a low-level SL1 challenge run? have fun. Want to do a power-run and grab all the best gear early on? Have at it. Want to try a 'non-standard' route through the game? go for it.
I picked the master key on the PS3 version and did a fairly blind-run --- I loved doing the item dash, figuring out where to go and where to avoid. Entering blight town, promptly getting flattented and thinking 'well .. maybe I'll come back here later', stumbling upon Havel -- the sense of victory once I finally killed him a few days later.
Running through Darkroot Basin and being in awe of the Hydra, sucha big free world to explore and run around and discover --- and having the master key played a large role in my initial 'awe and wonder' of the game.
