don't really need barbarian also, but usually they come with rage mechanics and that makes them somewhat unique (for some hulk fans )
Cipher -yeah, could just be a mage spec, but I guess they made a whole new mental skill system which is not the same as the tome dependent wizards.
If they can make paladins unique - so that there won't be same old smite, heal stuff that can also be made by a priest, then sure lets add paladins.
Bards- those guys.. the whole idea of them is so.. eew.. I'm too against them, so no, please no bards.
but there should be something to make the class really relevant, different.. that would mean that only bards should be able to use the social skills to max etc.. I really don't see those 2 as a whole class, sorry Subclasses maybe not more.