I believe this list from tv-tropes illustrates my point fairly well: [url]http://tvtropes.org/pmwiki/pmwiki.php/Main/FantasyCharacterClasses[/url]
In it, the "Fighter" and the "Magician" both has 9 sub-tropes, so you can do a fair amount of customization without even leaving the basic trope-area. The "Rogue" is down to 7 sub-tropes, it's a bit less, but enough to work with.
Now, here's the problem. The "Ranger" only has 6 sub-tropes, while it is only one less than the "Rogue" the sub-tropes of the "Ranger" overlap at least twice (sniper + magical both use special arrows, blades + dual-wielding both use bow/sword) leaving us roughly with 4 sub-tropes, about half of the other classes. 
The last tropeworthy class is the "Cleric" who overlaps with the other classes on 4 of its 6 sub-tropes.

What I'm trying to get is distinct characters with separate fields of proficiency. The mage does the mystical stuff, the fighter kills things and the rogue sneaks around. The ranger can easily be included in the fighters role, which would leave us with the cleric who (in order to be something else than the dude with the healing hands) has to double up as something else.