Well the best 2 class are by far Samurai / Ranger.
6Ac does not change much of the class balance in anyway. Since the real threat is enemy spell caster, and when you put a non Samurai in slot 1-2 it for them to be hit more to have chance to level up, they will also hit the enemy but it take less time to have them get a beating.
if you want 6ac for a paladin than the Scroll of Kominatok
(Paladin,Priest,Ranger,Sage,Samurai) is the one you want.
Now could we get a new misc item for the Fighter, or other basic class sure.
New item to get are always cool, and make something to hunt for.
I think tone up (the lesser class) is better than town down, so adding a few perk to Paladin or Ninja could be good to make them more a late game option.
The game is currently you run a party of basic class, until you get some gold and worthy item than you start building your real party of Samurai / Ranger. Using your first party to raise the lv up to your new party members to about lv 5 until their good to go on their own.
Now if we could get more choice of advance class I am all for it, make the Paladin and Ninja to be a good choice has the Ranger / Samurai.
Paladin could use their healing once per combat instead of once per rest and or they could get a high resistance vs enemy spell (like30% + their level with a max of 75%), and Ninja could *waste* a turn to hide in shadow, to be able to attack with a melee weapon even from slot 3-10 (for one turn) and they could get their insta kill chance to be same has samurai(the ninja should be immune to enemy spell the turn he is hiding in shadow). Samurai will still be best in melee slot 1-2 due to natural raising AC.
An Halberd could allow the basic fighter (perhaps Paladin too) to be able to attack from slot 3, instead of just 1-2.
http://en.wikipedia.org/wiki/Halberd