Using Adventure-Based Design, it is evident that a lot of 4e classes, as they currently stand, lack interesting ways to deal with tasks that are not necessarily combat based.
This is an attempt to solve that problem, by presenting some tweaks you can make to standard 4e classes, to make them better suited to the adventure, and not just the encounter.
Simultaneously, it will allow you to play characters who may not be combat-focused, who may depend more on diplomacy or stealth to avoid problems, without necessarily ruining the game.
The Problem with Powers
Standard powers that 4e PCs get are separated into two categories: Attack, and Utility. Both are combat-focused. Attack powers are used to slay monsters, and Utility powers are used to move, defend, and heal (though there are a few exceptions to this general rule).
The abilities that characters get to deal with the other three challenge types are relegated to one system: skills.
In order to make a class more suited for adventuring in general, we need to expand the scope of the powers they can get. Every character needs powers in four categories: Combat, Interaction, Exploration, and Discovery.
Skills, Skill Challenges, and Rituals
The skills that a character gets fall into three main categories of use: Interaction (skills to help you deal with NPCs), Exploration (skills to help you deal with physical obstacles and hazards), and Discovery (skills to help you unearth information and see the truth). Skill Challenges are a DM's tool to make use of extended skill checks in a way that the entire party can contribute to, but they still largely accomplish one of those three goals. Rituals (and the similar "Martial Practices") are effects that can help overcome noncombat problems, and also largely accomplish one of those three goals (with a few for dealing with long-term healing and item creation).
As explored in the Combats As Skill Challenges study, skill challenges lack interesting variety and character resource-use, when compared with combat. Rituals are well-known to be very expensive, and fairly impotent. So in order to make these non-combat elements count more, we will broaden the use of rituals as necessary or useful non-combat abilities, to solve detailed skill challenges like the ones presented in that section.
The Easiest Way
The easiest way to handle this, without affecting how 4e runs now more than necessary, is to simply add Interaction, Exploration, and Discovery powers. Then, whenever your character would gain a Utility power, they also gain one of those powers.
These powers work much like Rituals or Martial Practices do, but with distinct differences. They are more potent than Rituals, and have no cost associated with them. They are tied to a character's skills: you must be trained in a given skill in order to take the appropriate power. They take time to use (measured in a Short Rest or an Extended Rest), and last more than a single round (until the character's next Short Rest or Extended Rest, depending on how powerful the power is). They are also tied to a character's power source, rather than class — Arcane characters can only take Arcane powers, but any Arcane character can take any Arcane power. If you have more than one power source, you can select from any group.
These powers make use of the more detailed skill challenge framework to use, but can also work outside of it. They do not, however, work well with standard skill challenges — it is recommended if you use a skill challenge to construct one using the more detailed guidelines on this website.
Replacing Healing Surges
"Healing Surges," in this model, becomes something of a misnomer: the character can spend them to heal, but she can also spend them to recover from many sorts of failures. It also doesn't make sense for especially "hardy" characters to necessarily have more — constitution isn't necessarily a great savior from a social failure.
Instead, characters have a number of 8 Recovery Points each. Instead of spending healing surges, characters spend Recovery Points to help stymie the efforts of their foes to win. "Second Wind," for example, will use a Recovery Point to recover a hit, rather than a "healing surge."
Replacing Action Points
Similarly, "action points" loose their value in a combat system where the action economy isn't spent, and isn't spent as much. Replacing Action Points you have "Adventure Points," which work the same, except they allow the character to re-roll a failed check, rather than giving them an extra action.