Cant confirm that, I made one in the hope that it would be difficult but it sadly is not.
If you use Conjuration and/or Illusion that is, if you only have Destruction as a matter of dealing with multiple strong enemys at once you are obiviously screwed, but who would do that.
It would be nice to see some specs and used spells of other people, maybe that would give a hint to where the problem is.
Mine:
Level 30
Conjuration 75
Destruction 70
Illusion 52
Restoration 35
Light Armor 28
Common used Spells and Shouts (Combat related) :
Lightning Bolt
Wall of Thunder
Storm Atronarch (until recently Fire Atronarch Instead))
Dremora Lord (until recently Ice Atronarch instead)
Revenant
Frenzy
Novice Healing thingy
Whirlwind
Perks:
All the 50% Magicka reductions for the spells above exept Illusion
+50% Shock damage
Staggering for Shock
x2 duration for the summons above
x2 summoning range
Dual casting power up for Conjuration and Destruction
+25% Magicka Regeneration
+2?% light armor
Items:
-35% Destruction Spell cost
+50 Magicka
+20% Sneak

20 Armor total
No potions usually, rarely magicka potions if any.
Mouse and Keyboard (I suspect that to make a huge difference)
Note that this is not a recommendation for how to spec a Mage, for example I took shock because it looks cool, use crappy equipment so it dosent get more boring and summon undead a lot because I love Zombies

Edith Edited: Oh, and 180 health, 100 Stamina and around 280 Magicka. Difficulty is Master.