Not sure, why it is not working for you as I have created the mod as you described and it works for me perfectly:
https://dl.dropboxusercontent.com/u/23858825/FasterThanYours-ChangeDefaultProductView-v5_1_0.tar
Note: are you cleaning your browser's cookies after module activation? The problem might be is that current mode selection is saved into session, so you might not notice the change even though it is there.
Tony.