Mark-
You bring up a great point about fishing. Most all of the guides I have spoken to down in Key West will have nothing but a notched transom for this reason. On top of that most want a covering board/engine shroud over the outboard to prevent line tangles, keep water out, and quiet the outboard.
like this on the Conch 27:
Its hard to argue with the leaders in CC fishing, but I will. On my 25 there must be 2.5 feet from the cockpit end and the far end of the OB. I have never had an issue or lost a fish because the line snagged in the OB. Perhaps if I was a guide and took unexperienced angles out, then I can see the reason but if you can control a fish I see no problems with a bracket.