Psion
Adventurer
IMO, the seminal difference between 4e and the prior incarnations of D&D is this: In 4e The world exists based upon the PCs interactions. (For example: In this type of role-playing minions make sense. The power of a creature is viewed only in relation to the PCs powers.)
The earlier editions of D&D believed this: The world exists and the PCs interact with it. (For example: In this type of role-playing minions do not make sense. Each creature has power based upon it's place in the world, regardless of the power of the PCs.)
Both types of play can be a lot of fun, but they are entirely different ways of viewing a role-playing game and, I believe, this is the primary reason for the dissatisfaction many of the the D&D audience has with 4e. The basic assumption of what type of role-playing game D&D is changed.
I think this is worth noting for anyone in the audience who is having a fundamental bit of trouble understanding why some folks (especially those with broad experience with pre-3e D&D) are experiencing a bit of a style clash with 4e. For us (I'll be bold enough to presume speak for the group here), kobolds are NOT something that should be threatening high level characters. Kobolds occupy the mindspace of "weak low level challenge", and for them to fill some other space other than as an oddity (such as the kobold sorcerer lich in Bastion/Dragonwing's Villains) is to define something that is not a kobold.
I have been using the idea of "sliding scale heroism" in other games (like Spycraft 2.0), and don't object to the approach for its own sake. It's only the way that the approach warps the landscape when speaking about D&D that seems wrong to me.
It's worth noting that you don't have to use 4e this way. I know if I were to ever run 4e, you'd only see unique kobolds that weren't minions and you'd never see a Balor minion regardless of level. And indeed, I wonder how many DMs who moved on to 4th but preferred an "older school" feel do just that.