Well, its certainly more difficult to create a new class, whether ballanced or not.
In 3rd ed., it was pretty easy to create a class by choosing your attack bonus progression, save progression, starting proficiencies, skills/level, spell selection (if any), and any class features and/or additional leveling benefits (such as more feets or additional uses of class features). Not too hard to take a palladin, drop his class features, give him sneak attack and access to the shadow domain (along with creating a spell creation chart), add some custom class features and voila - you have a new class, the Shadow knight. Ballancing said creation was another issue, but at least the creation itself was relatively easy.
For 4th ed., with each class having its own specific powers - not so much. Basically, you need to create 3-4 powers per level, and paragon paths... so, nothing to be embarked on lightly.
For myself, however, that's not really a problem. Aside from the custom cleric system in 2nd ed. (which tended to nerf rather than buff your character), I've never really had any real desire to muck around with classes.
Additionally, given that the fluff and the cruch are somewhat divorced in 4th ed., reskinning is far easier than ever before. Combined with the multiclassing and hybridding rules, one can get a pretty broad range of character concepts with the existing classes.