I've been lead to believe that V.5 will search & replace multiple lines (BIG issue...)
A customizable toolbar would be (IMO) the best option for all the copy & paste icons arguments.
When you're selecting a font for a quick tag, there's no font preview. But when you're selecting a default editor font there is! This could act as a temporary work-around for selecting a font quick tag, but doesn't really make sense. Put a font preview box for the <font> quick tags.
A system tray icon would be excellent. Gives you a way to keep the program open without using up taskbar space.
Also a Similtanious Multiple Undo feature is very handy. Rather than holding in CTRL+Z until you gone to far, then pressing CTRL+SHIFT+Z and going back and forth like that, this feature would allow you to Undo Multiple mistakes with two clicks of the mouse. Microsoft Word 97 or higher has this feature, and it makes for a really quick and easy boo-boo fixer.
I may have mentioned this b4...oh well, what the hey. An option to store settings using an INI file or the registry would be useful. Allows easy settings exporting and importing.
Code chunks that I use frequently would benefit from a User-Defined text block insertion.
Two more things: a character map with auto-insert and a hexadecimal mode would be neat.
Hope that's not too much
Good luck w/ V.5