Exhibit A: Tweetie, which I love in both its Mac and iPhone incarnations. The iPhone version was completely rewritten for version 2, and it's great, but the rewrite was supposed to make feature parity with the desktop version more doable. Well, it's been months, but there's still a lot that Mac version can't do, like new-style re-tweets.

Exhibit B: NetNewsWire: this is another good application in its Mac and iPhone guises. And again, there supposedly was a a new architecture on the way for NetNewsWire 4, but both the desktop and iPhone versions are kind of lagging in refinements and fixes (although Google Reader Sync finally seems to be under control). NetNewsWire 3 was released in 2007.