Maybe I'm missing something here, but can't you just select an dock icon, right-click, and choose "Options / remove from dock?"
Whoops, I didn't read carefully. Uninstall, yes.
If you haven't invested a lot in customizing the apps you want, you could remove the entire Office suite (I think there's an uninstaller for that).
Then reinstall but choose "Custom" and only install Word, Excel, and Powerpoint.