Tulo is a health risk, but he's a truly unique player. Only maybe Hanley Rameriz is in his class. Adams and Miller are nice young players, but they are replacable, espeically Miller.
Contracts have never seemed to hinder StL. Tulo isn't going to be making that much more than Beltran did (I think Beltran was making around 12 million/year). More expensive, but not crippling. If the Cards get Tulo and Tulo stays healthy, the Cards will be terrifying.