I don't really buy either of those.
For one, at best, Brian Anderson and Aaron Rowand put up very similar defensive metrics in 2006 for their respective teams, and everyone agrees Brian Anderson had a good/great glove in CF. Offense wasn't the issue in 2006, it was the pitching staff and defense, specifically when Mackowiak was in CF.
Second, Obviously at that point Frank was just a DH.
Thomas in 2006: .270/.381/.545, .926 OPS with 39 HR's
Thome in 2006: .288/.416/.598, 1.014 OPS with 42 HR's, and provided much-needed balance in that lineup hitting from the left side.
Thome/Rowand was a good move and still is today. Was pretty well documented Ozzie didn't like Anderson, but his bat wasn't hurting them with a stacked lineup around him.