Rework Example:

Introduce mana regeneration or resource efficiency bonuses for elemental skills, especially for Diablo 4 Items Fire or Frost builds. For example, Fireball or Meteor might have their mana cost reduced by 20% when used consecutively.

Add more mana regeneration passives that activate when standing still or after successful crits from elemental spells.

B. Elemental Synergy Adjustments
Current Issue: Some elemental trees, like Frost, might feel less effective compared to Fire in terms of damage output and utility.

Rework Example:

Improve the synergy between Fire and Ice for Frostburn builds. Fire spells might have a chance to freeze enemies who are already burning, enabling devastating combos.

Frost Nova or Ice Armor could be enhanced to not only provide crowd control but also boost damage resistance when active, offering more survivability.

C. Mobility and Survivability
Current Issue: Sorceresses are fragile, making it hard to stay alive in harder content.

Rework Example:

Introduce a teleportation mechanic where Teleport reduces incoming damage or grants immunity to certain debuffs for a few seconds after casting.

Improve defensive skills, such as Energy Shield or Ice Barrier, so they better protect against overwhelming amounts of damage.

3. Necromancer Class Rework Example
The Necromancer is a pet-focused class with powerful summons, but players report that minions sometimes become ineffective in high-level content, and Essence management can be tedious.

A. Minion Reworks
Current Issue: Minions often feel too weak in endgame content or boss fights, and they don’t scale well with increased difficulty.

Rework Example:

Introduce minion buffs that scale with Essence spent or generated. For example, each time you cast a Corpse Explosion, your minions get a temporary boost to damage output or health.

AI Improvements: Enhance the minion AI to make them more responsive and effective at targeting high-priority enemies (like bosses or elites).

Minions could get access to more advanced abilities, such as shielding allies, debuffing enemies, or crowd control like stunning or slowing.

B. Essence Management and Skills
Current Issue: The Essence resource for Necromancers can be difficult to manage, especially when transitioning between minion-focused and spells.

Rework Example:

Introduce more Essence generators that also interact with Corpse Skills. For example, Corpse Explosion could have an additional benefit like regenerating a small amount of Essence for every nearby corpse.

Skill Synergies: Rework the synergy between Necromancer’s curses (like Decrepify) and Corpse Skills to further improve damage output.

C. Survivability and Damage
Current Issue: Necromancers are often weak in terms of personal survivability as their minions do not always absorb enough damage.

Rework Example:

Give Necromancers a more significant self-sustain mechanism. For example, casting Bone Armor or Blood Rush could give the Necromancer an automatic healing effect based on damage dealt.

Rework Bone Golem to grant temporary damage reduction to the Necromancer as it absorbs damage.

Summary
These rework examples for Barbarian, Sorceress, and Necromancer focus on improving resource management, combat synergy, and class-specific survivability. Blizzard typically focuses on maintaining a delicate balance between enhancing a class's core identity and addressing gameplay issues raised by the community. As Diablo 4 continues to evolve, the rework of these classes is crucial for keeping the game fresh and balanced for both PvE and cheap Diablo 4 materials PvP experiences.