Hybrid class, using mana points - I've chosen mana, not energy because of Spellbreaker's deep connection to (especially arcane) magic. (It's like 'fight enemy with his own weapon'.) Class able to wear only cloth and leather armour at first, but then becomes capable of all armour. Able to wield Swords, 2-hand swords, Shields, Daggers, Dual-blade weapons (such as Warglaive of Azzinoth or Spellbreaker's weapon from Warcraft3) and Wands as ranged weapon (Spellbreaker doesn't depend on technology so not guns and not Bows, obviously).
Talent trees named: Spellbreaking, Arcane Combat and Energy Control. First focuses on burning enemy's mana and interrupting actions by various spells. Offensive. Second helps to use buffs and upgrades abilities used in close combat. Defensive. Last tree maximazes healing and regeneration and gives beneficial effects to all party members also containig abilities capable of stealing enemy's buffs. Supportive.
Dividing talents in those 3 grups gives you chance to create 3 completely different in play-style characters.
Spellbreaking allows you to cast powerful arcane-based spells that would annoy each caster class. This talent tree makes your character a battlemage, that after spending last talent points becomes able to cast instant spells on mount and cast and channel spells while walking. (That's right "walking", not "running" - press "/" in game and you'll see the difference)
Second tree, Arcane Combat, focuses on melee. Best abilities require having 3 buffs on, so you'll need help of other classes to make them work, but they're worth it. Upgraded Boomerang ability enables you to throw your Dual-blade weapon at enemy, dealing additional damage and stunning him or her before charging to melee. This tree also provides special ways of resisting spells, making you the best tank for spell-oriented bosses.
Last tree, Energy Control is maybe more controversial, but also the most interesting choice. It provides wide range of abilities that gives various bonuses to you and your party members. It's also the most universal one, increasing your stats and allowing you to heal entire party when reached 60th level and ressurect since 45th level. Maybe not the most effective pvp choice but Energy Spellbreaker's would be great support for every raid group. Class available exclusively for Blood Elves and Humans (other races would look quite strange as Spellbreakers - maybe not Night Elves, but they don't tolerate arcane magic)
Strong points: - Variety of different abilities (hybrid) - Mage-killer (including all mana-using classes) - Great supporter with talents invested in energy control - not bad dps - may wear mail armour since 30 lvl may wear plate armour since 50 lvl - quite good at pvp - useful in raids -interesting gameplay, introducing new gameplay mechanics such as casting instant spells when mounted, buff-requiring abilities and other depending on your current mana - powerful transformations (Arcanemeld, Spellcaster's Shroud and Cristalform) - chance to play well-known character from Warcraft3 - cool-looking, already in-game Spellbreaker armour - no problems in adding additional lore information to World of Warcraft and adding this class
Weaknesses: - no healing, only healing-boosting abilities - only one weak ressurection ability that needs spending a talent point - spells with long cooldown - may have problems with enemies not using mana, but some talents makes it easier - not the best choice for pve at first - Transformations requires large amount of mana and have long cooldown - not the easiest class, especially with energy control talents
I do not spend more space for writing down all talents, so here is link to Spellbreaker talents. Enjoy!