Paladins aren't ridiculously unbalanced. Their class feature is survivability, but the DPS they put out isn't too good, they can't pull any mobs except by creeping closer to them to get their attention and they can't hold aggro up at the upper levels. All the bitching you are hearing now is from people in their 20s and 30s and they see how well a Paladin shines when soloing.
Let's look at this in a linear fashion.
Paladins get:
+tanking
+healing
+ressurection
+buffs
-pulls
Clerics get:
+healing
+ressurection
+buffs
-fragility
Warriors get:
+tanking
-everythingelse
The paladin has the features of many other classes, with no real disadvantages beyond the inability to pull easily.
I play a druid. It is true that we can tank like a paladin and heal like a cleric. However, we can't do both at the same time. This makes our survivability really hard to ensure. For example, sure, you can buff yourself up crazily, pop rejuv and regrowth (for two +regen temp buffs) and switch to bearform... and you will be invulnerable for 10 secs. However, if you're tanking as many mobs as a paladin will regularly, your HP is going down fast. So you get to half, where a paladin might start to think about healing, but wait... if you shapeshift back to normal form to heal, you're going to be back to shitty damage reduction. Not only that, if you don't grab the Shapeshifting talent to its max to reduce the casting delay after shifting, you're fucked. It's very unlikely you'll be able to recover if you shift back.
If the bear form could even do something as small as cast rejuv, the druid's effectiveness would be increased twofold. Add regrowth or healing touch, and it becomes exponential.
As for hunters, there's no reason for what you just mentioned. Set the pet to passive and simply use the attack command, and you have no problem. However, it is true that hunters generally add nothing to a party's dynamic; no real buffs, nothing but damage, which rogues or mages or whatnot can offer better.
Warlocks are great soloers in that they are almost as invincible as the paladin, with a lot more tactical options and pulling ability thrown in; the voidwalker gets an insane amount of HP and soak relative to its level. The only thing warlocks have to watch out for is the tendency of the voidwalker's taunt to fail reliably on anything more than +1 levels above it.
Rogues... rogues are just BADASS if they're well-equipped. I play a pair of duo rogues with a friend, and we rape anything short of elites. There's even a pretty hilarious route you can go if you want to have two rogues who can take out elites (Preparation + Improved Ambush should tell you all you need to know).