Mages in Parties: Gandalf, or a Glorified Archer?

[Mastikator]

Mages shouldn't step on anyone's toes, they should limited to the impossible like inscribing magic runes on walls, turning people into stone and communicating with the dead.
Direct attacks should be the domain of warriors, larceny should be the domain of rogues. If mages should be able to make direct attacks then frankly warriors should be able to do supernatural feats as well. If mages can do larceny then rogues should be allowed to do magic. And since rogues can fight, warriors should be allowed some larceny.
Either segregate the roles of the classes consistently or let them trespass on each others roles consistently.

Edit- also if mages are just glorified archers, why have mages?