Version: (using KDE 4.2.3) OS: Linux Installed from: Unlisted Binary Package The list of standard keyboard shortcuts in lacks some common commands like "New Tab" and is not used by all applications and all commands respectively. For instance konsole does not consider these shortcuts at all (even if the standard shortcut for copy is not Ctrl + C) and Konqueror uses its own shortcut for Select All although this command appears in the list of standard shortcuts.
We can't use many standard shortcuts in the terminal because they conflict with terminal applications. For example, Ctrl+C kills the current application in the terminal so it cannot be used for Copy. Instead what I try to do is take the standard shortcut and add the Shift modifier. So copy is Ctrl+Shift+C, search is Ctrl+Shift+F.
That's perfectly clear, yet I am using Meta+C and Meta+F (like Apple) as standard shortcuts which does not conflict with Ctrl+C. In my opition, it would be better if Applications could "overrule" standard shortcuts but only if they actually cause a conflict (like "use standard shortcuts except for Ctrl+C, Ctrl+D,..., use Konsole Default for the actions assigned to those shortcuts [and resolve resulting conflicts the same way]"). Simply adding Shift may conflict with other standard shortcuts.
Meta+C, Meta+F could conflict as well. In practice I assume the applications you use don't use those shortcuts but to handle the wide variety of terminal applications that exist I make the blanket assumption that <Single Modifier> + <Letter> shortcuts are reserved for terminal programs. Konsole is one of very few programs that have this kind of limitation and on its own it doesn't justify the effort of adding a generic mechanism to handle this sort of conflict in KDE.
There are tons and tons of shared shortcuts now. If there are any problems, please file a bug on the affected app. FWIW Konsole can't use Ctrl+C for copy because ctrl+C sends the termination signal in a terminal emulator.