Well, in terms of functionality, they are indeed enough. In terms of flexibility, however, they are not. If I want a simple thing like having my game save its games under \SavedGames and not under \saves, I can't. Or if I think the games should be saved under My Documents\Game Name\Saved Games, I can't either.
Of course, it's not an absolute must, but I think a good game engine should strive to be as flexible as possible. So if it's a quick and easy thing to do, I think it should be configurable. If, however, it's a mess to start with it right now, then forget all about it...
I thought of something like the REGISTRY_PATH in the startup.settings file. Just like the REGISTRY_PATH is a relative path, assuming HKEY_CURRENT_USER as the root, the new setting could be relative as well and assume the root as either the game installation folder or the "My Documents" folder according to whether the "Personal savegames" is enabled or not. Leaving this setting blank could mean to place the saved games under the assumed root.
Anyway, maybe I'm just nagging but nagging people like me is what makes an engine more robust and flexible in the long run so I hope you won't be too annoyed...
This thread should be moved to the "Wishlist, suggestions" forum now, btw...