That's not really possible since it would require all applications to follow the same guidelines for using shortcuts. And obviously they do not.
Most programs will get you to preferences with alt + e but the next letter is different in various programs.
Some examples ...
- You get to preferences for Nautilus and Firefox with alt + e, n (prefereNces). P is for Paste but the letter seems to be different since
f looks available)
- If you want to reach preferences on Chrome it is alt + e, s (for Settings) and then shows you the inline settings from the icon in Chrome. The P accesses Paste (Preferences does not have a letter and you might even consider this a bug: the text should have been named Settings).
- Shutter on the other hand has alt + e, p (Preferences).
- Terminal is even more weird: it uses alt + e, o for prOfile preferences.
- Preferences in USC is called Software sources.
You might be able to track down all the text segments in the software but that would be time consuming and temporary: the 1st time you update you might overwrite all your changes. The path you can take to get what you want could be to file bugs against alle applications that do not use for instance the method Nautilus and Firefox use. Seems impossible to me to get done.