Your example with the goblin thing is ridiculous, have you ever tried doing it with a melee character without any magical effects? yeah though so.
In a word, wizard have always been OP because of the ridiculous effects they get, chameleon, invisibility, paralyze (not exploits) and weakness (stack, exploit).
Remove the OP effects and magic is not OP, keep the OP effects and it will be OP. Compared to warrior, thief.
Just btw, I'm pretty sure there are tales in ES about warriors who were so mighty they could swing the sword in through the air and set it afire because of the force behind the swing and thieves as skilled to be able to steal of all clothing from a person, right in from of their face while they are awake. So meh.
Now there's some sense. Goblin warlords are the problem, not the spell power. Magic user players always want there already powerful class to be even more powerful. And it's usually the same argument. I can walk into a town, fry everyone no problem, but when I come to the most powerful enemies in the game, it's a bit of a challenge, so it doesn't feel like real magic. It is less challenging than with a warrior or a thief.
You want to feel powerful? Like a true wizard? The ones in the stories. Didn't notice Gandalf one shotting a troll with a fireball. Merlin didn't take out armies with bolts of lightning. In OB you could do some ridiculous stuff as a mage, but it's never enough for some. You see the same argument with recharging magic weapons. " I hated using soul gems, my sword needed recharging every fight." Yes it did, if you had 25 points of fire damage. The very best weapons run out quickly, why is that a problem?
Honestly, if you had high alchemy, high destruction, and plenty of shield and fortify magicka, and felt underpowered, well I have no sympathy.
As for fingers of the mountain, one it was what you got for betraying the guild, two it's magicka cost is so high because it is instantaneous, all other destruction being over one second, not the best example to prove the point.
[btw, always played mages, never used weakness stacking, put the difficulty up a bit every few levels, never had a problem myself]