Garret is a hell of a lot better than nothing--he's well below Bernice but it's not like trying to tank post Awakening bosses with silvers is a great idea either. Otherwise, it's time to start looking at Awakening as well some of the more specialized units that you may not use constantly but still come in handy on certain map types. For example, a ranged melee unit would be nice, although I wouldn't put off awakening to get Saki.