THE OP IS DAMN RIGHT!
1. No class should be much weaker than another! This is called BALANCING! So why should a mage (A MAGE!!!!) be weak in mid and endgame??? When its at the first levels (like in nearly every other RPG) it can be tolerated -actually expected - but later on a mage should rule the world!! It is a powerfull spellcaster and lord of destruction. A damn horrible DOOM to all foes!!
2. It is a GOLDEN RULE that cross-classes succumb to single classes in the very basics! (Not actually in every skill but regarding magic, a pure mage should blasts every magical crossclass, just because it IS a pure mage). This is about specializing! If i choose to skill single class I expect to be the unchallenged MASTER of it.
3. I do not want to play a cross class (see point 2). As a pure mage I should have had the possibility to rule even in mid and lategame!! My damage output should be ENORMOUS!! Cause I am A MAGE! I am fragile cause I wear cloth armor and I do not have much lifepoints. But I should eradicate each reaking foe with one THOUGHT!!
I spend many hours to explore Skyrim, grinding money for my horse and first house, collecting herbs and so on. But after reading this posting I think I will change to knight or hunter (Level 7 atm). My heart bleeds to do so but realizing I skilled wrong and do not stand a chance in lategame as mage, svcks!
(capital letters in above text should not be seen as screaming but as highlighting important content)
AYE
Thats how it should go, but a smart mage in this game wears plate armor because robes are useless, lol. You are exactly right, the whole concept is broken. This game forces you to play a hybrid. It just is not fun anymore for people who want well thought out characters that don't take a little of everything. Specialising in magic is not an option in this game, not if you want a decent character that feels and plays like a mage