neceros
Adventurer
Again, multiclassing in previous editions was required or wanted because of design flaws. A fighter could not be as powerful as a wizard, so she trained as both to be both.Sammael said:4e effectively bans multiclassing for characters under level 11, introduces the new, highly restrictive "multi-feating" concept, and creates a number of problems of its own, not the least of which is the loss of elegance introduced in the 3e concept. A lot of 4e multi-feating problems stem, IMO, from the new concept of powers, which is very problematic in and by itself.
In fourth edition, you don't need to multiclass for your character concept, unless that character concept is literally dabbling in other classes or half/half. If you want to play a fighter mage, be a Wizard who has some feats aimed to proficiencies and Toughness. If your mage needs to be a defender, then multiclass into a defender archetype.
Multiclassing just isn't as much of a requirement as it was in earlier editions. Multiclassing is less powerful because you don't need it anymore.