I never played either Diablo
Then how can you even comment on the subject in question...
The classes from the previous diablo (II) were crap, with poor design and ballence.
Getting a hammerdin and killing stuff was fun and all, but honestly you can only repeat that twice or so before the game gets repetitive. Everyone using bots killed the game for me, as there is no way I can afford enigma and other crutial items when bots (which are constantly banned and thus lose all items and replaced with the same insane gear) can aford to pay 100s of times more than me.
An example is playing a barbarian and then playing a sorcress. Everyone will instantly notice how easy the game becomes with the sorcress. Where as the barbarian becomes near impossible to play at late nightmare and hell difficulties due to shit DPS output (unless you somehow get crazy gear for it which need the sale of hell drop only items), the sorcress can skip most badies she can not kill and kill bosses with ease (and get their loot). Same problem with the ammazon, although better than the bard due to her insane free tanking unit, she can not kill stuf nearly as well as 6K+ frost damage or 12K fire damage. The necromance was ok, but the AI sucked meaning minions often were removed due to wandering too far and you could not raise a full army due to the servers kicking you (anti duping crap). Palidin was another sorcress class, with the smiter being able to solo every boss (even ubers) with no problem at all and in hammerdin form had much more killing power than any sorcress (let us not forget how easy it was to 75 all res on hell with a pallidin due to their rigged shields). Assassin was ok, as kicker it could give a smiter a run for its money and its traps beat any lightning sorcress, however low res, poor block and no inniate teleport mean both smiters and sorcresses can perform better for less. Druid was a piece of crap, any morphing at all ruined your ability to use teleport from enigma, all non buffing summons were usless in hell, elemental druids are usless compared to elemental sorcresses and morphed melee attack abilities pale compared to those offered by the pallidin.
So what was the ultimate team in that game?
Barb, druid, druid, pallidin, pallidin, pallidin, pallidin, pallidin.
One barb for +defense + skill +HP/mana buff (good allround buffing, can be replaced with extra hammerdin with CtA for much less effect)
2 druids for the +HP +damange/FAR buffs (only for those buffs due to the insane effect on team HP and the melee characters)
5 pallidins with all kinds of crazy different aurs (mostly hammerdins but atleast 1 smiter)
All A2 mercs of different auras (only duplicates being holy frost)
This team would be so powerful, nothing could stop it due to over 700% extra damage +50% FAR (flat bonous, not shitty weapon bonous) and over +200% HP (as well as lots of other buffing auras).
Ofcourse this team is entirly pointless as being able to kill enemies 32 or 64 times faster than required is pointless. Frankly 1 hammerdin with good gear can solo 8 player difficulty on hell effortlessly with the exception of a few bits (which 1 single backup character can overcome).
I like how in D3 they are going to emphisise cooperation. I would not mind 8 player difficulty being completly impossible to solo on hell mode.