and on the mage's usefulness front, if your wizard is just sat there casting magic missile, ofcorse they suck, i play a level 3 wizard in one of my 4ed games, and have found countless ways to use cantrips in a combat situation, from using mage hand to deal touch efects, using prestidigitation to set out the flames on out warlock (ongoing fire damage), heat up our fighters blade with prestidigitation to add a fire keyword (i rolled an arcana check to see if i could just heat up the blade and not the handle, hurting our tank), ready an action to tap a guy on the shoulder just before someone attacked them (magehand) to give them combat advantage, a similar thing with ghost sound, undo a chandelier with magehand, harrier familiar my tiny gelatinous cube familiar onto the bowstring of a goblins bow to snap it, ready an action to cast light in an enamys face as they are about to atack our fighter... and thats just the last few encounters...
i might have a lenient DM (well he makes me roll arcana check/whatever else he finds appropriate if its something he deems challenging/gamebreaking) but hes mostly under the impresion that if its something cool, and imaginative, but not gamebreaking, then players should be able to do it. of course i give up quite a few actions for these stunts, but its one of the things i find fun about playing.