Artificer is great for soloing, though it's pet can get a bit fragile in groups. It's also one of the best ranged attackers(up there with elemental sorcerer). The druid's pet is better in groups(since it's designed as a dps), and the druid can fill several roles(melee dps[wolf or humanoid forms], tank[bear form], dps caster[any form], or healer[elemental or humanoid form]), with healer being it's weakest role and tank or dps caster probably it's strongest.
a lot of mmos do have a lot of classes, wow has 11, eq2; 13(I think), and even guildwars 2 has 8.
And the base material(3.5 dnd) had at least 30 base classes. It would be neat if they added multiclass prcs though(a few of the later base classes would also be interesting, particularly the duskblade, binder and dragon shaman/dragonfire adept)
Up front, I stopped playing about a week before the expansion. I played the game a ton (4x TR Barb, and 4x TR FvS along with a few alts), owned all the packs and classes (except WF, robots don't have hearts;) ) and think it was one of the best MMOs out there.
But I did not buy the expansion ahead of time, due to the track record the have of putting out new content that is super buggy, and I'm very happy I didnt spend money on it. All their recent updates since the expansion have had game breaking bugs, with recent events (mybar and the cove) being closed down due to issues.
The current devs and producers just dont have a handle on the code that they have, so minor changes and bug fixes make huge wave in unintended parts of the game. Its a real disappointment to me, because their quest system and character building was best in the MMO game IMO.