[RPG] How to make a more offense oriented Paladin, like Finn from Adventure Time

Combat is frustrating when you are unable to act. Combat is challenging when you are threatened, at risk, but able to respond.

In order to reduce frustration, make things that reduce actions with save-ends effects staged. A stun or dominate should never be the first thing dropped on someone with a save-ends (End of next turn is fine, however.)

I prefer using the progression of: Granting Combat advantage, dazed, stunned for my save-ends effects that were originally stunned, and dazed -> Dominated for my dominates, especially if they originate from an at-will.

The best way to make combat challenging and exciting is to scatter terrain features that both allies and enemies can use to great (and lethal) advantage while stationing fairly beefy enemies at them. Then the combat has a sub-goals of, for example "control the [really nasty thing shooting fire at us] and reorient it so we can rain fire on the enemies" as opposed to the "clear the battlefield." By increasing tactical complexity, you increase the challenge, but also increase the opportunities for innovative tactics and player self-expression.

First of all, this is not so much a problem, as a design decision. 4e is purposefully designed to let characters start afresh every morning, to make encounter design easier for the DM (and published adventures). Another thing worth noting is the fact that hit points are highly abstract, and don't necessarily represent physical damage characters sustain:

Hit points represent more than physical endurance. They represent your character’s skill, luck, and resolve—all the factors that combine to help you stay alive in a combat situation. - PHB293

In fact, as the term bloodied suggests, until the character has lost half of their hit points, they're not even that. With this out of the way...

Two ideas come to mind. One is to limit the amount of healing surges a character regains with each extended rest. Probably a flat value modified by sleeping conditions and available medical care, something along the lines of:

Everyone regains 3 healing surges after an extended rest. Following circumstances may increase this number:

+1 - Moderate Heal check / +2 - Hard Heal check

+1 - Moderate Endurance check / +2 - Hard Endurance check

+1 - Decent sleeping conditions (warm bed roll, rations & water) / +2 - Excellent sleeping conditions (hard bed, hot meal and grog)

These numbers, of course, are not at all tested, and can be modified according to your preferences. This doesn't really change the balance of the game, as long as you're careful with the number of encounters you throw at the tired party.

The second idea is to award a wound condition to a character every time they drop below 0 hp. Broken leg, -2 to speed. Fractured arm, -1 to attack rolls, etc. Each damage type could impose its own wound - WFRP had something along these lines, IIRC, and so can be used for inspiration. Healing these wounds may require time, ritual magic, or burning healing surges at the end of an extended rest (in which case these two can be combined). Note that this actually changes the way characters operate, and so should be approached with extreme caution.