As for this point, if we're talking about better than his career numbers, you're right. However, I was referring to a better hitter than he was last season (and better than I think he'll be next season). Not to mention that if we're just looking for a DH, it really wouldn't cost that much. "Younger hitters" is a pretty big group.
This really doesn't work since younger, better hitters usually are expensive in FA or you have to trade something valuable to get them. If this is your plan I hope that you reconsider because it's more likely that you are getting Clete Thomas part II as a replacement.