Exactly, which is why I said possibly better. He's an OF, defense only matters so much. He's good for five to ten less HRs or so than Dunn on average. He's clearly better than Dunn, but it isn't by a mile.
The fact is it shouldn't have to be an either/or proposition. Adding to the team with Werth while keeping Dunn would've been huge progress, giving the team a truly fearsome heart of the lineup that could've filled the stadium with curly W wearers. Swapping one for the other is treading water on a 5th place team, and was almost certainly necessitated by the cost of having two major contracts on the roster instead of one.
As has already been pointed out, we're back to the ownership shell game as certain contracts have to come off the books for others to be added. That it's on a larger scale this time around doesn't change the underlying fact, as potential season ticket holders know full well. The move's oddly reminiscent of when the Lerners got shamed into signing Dunn the first time around, having let the perception and reality sink to all-time lows before making the overpaying move that smacks of desperation.