Give an actual reason why. Let's take 7 games in a week. Morse starts 5 at 1B, Hammer starts 5 in LF, Huff starts 4 split between the two spots. He gives the LHB off the bench when he's not starting etc. Werth automatically upgrades the offense and defense. We also get the picks for Dunn. That's better short and long term.
Ok first. It's not better short term. If you re-sign Dunn, and add Werth, you've already got more production than what you propose. Unless you're saying after dumping Guzman's 8 million dollars the team doesn't have 25-30 million to spend, which they should.
Second, Huff is three years older than Dunn, Werth is a year older. So, when they're breaking down in 3 years, especially Huff... and Dunn is going strong... will it still be better? Of course not.