In Next, they seem to have a design goal that, for spellcasters at least, they would rather make a spell that does something or put rules for some kind of effect in a spell rather than make a new general rule or class ability, for example, see the counterspell spell. I kind of like this, it helps with the idea that you get to choose your own complexity(by class, feat, and ability selection), it also makes there less generic rules to learn. A shining example of this is the Turn Undead spell. Clerics cans till turn undead, but it's not a whole new ability with it's own rules. If a cleric is going to get some new function or ability, it should be a spell(or a domain). If you can't fit the ability in one of those camps, you probably should make a new class.