My thoughts on the Pyromancer: http://www.herocraftonline.com/main/threads/lets-talk-about-the-pyromancer.35328/
That post has a lot of nitty gritty mechanics written up in there, but I think that the information contained within it is important when considering the future of the Pyromancer.
I've thought about this a lot, and I really think that the Pyromancer could use some love. It's a great concept with a lot of potential, I just don't see the potential actually being used properly.
Someone once brought up Dark Souls (Kainzo perhaps?) in reference to the Pyromancer. I think this is a good reference. It shows that the Pyromancer doesn't have to be entirely focused around fire. They use dark magic--they curse, they twist, and the distort. Adding in another ability to give it a push towards this direction is something I think would be worthwhile.
So here's what I propose.
1. Remove Fire Weapon
The Pyromancer already has any player that he targets on fire 100% of the time. Between Fireball, Blaze, Fire Armor, and Chaos Orb, it is very rare that a player fighting the Pyromancer is not on fire. It's unnecessary fluff that doesn't actually aid him in any way.
2. Add Curse
One of the biggest weaknesses of the Pyromancer is that he a melee caster that can't actually fight any melee classes. In a straight up fight, despite the Pyromancer's large amount of weapon damage, he does not have the ability to defeat another melee. If he wishes to fight a melee class, he must kite them using Fireball and Wither.
By adding the "Curse" ability, you allow them to stand a chance. It also, coincidentally, fits right in with their theme of dark magic. It would add a bit of "melee" flavor to the Pyromancer without directly buffing their melee damage.
3. Rework Chaos Orb
Chaos orb is an interesting ability. When Ender Pearls were enabled, it allowed you to get through 1x1 holes, jump up ledges, and even juke your enemies by throwing it off of a cliff. Yet, it was also your highest damaging ability. You could try and use it for utility, to gain an edge on your opponent, (and sometimes as an escape mechanic), but if you did so, you lost a large amount of potential damage. It was truly an interesting ability.
However, due to the Ender Pearling fiasco that resulted in many players using Ender Pearls and Chaos Orb to travel through LWC doors and solid blocks, the ability has lost it's luster. Now, I'll admit, I'm almost entirely at fault for this, as I was one of the first players to truly abuse it in an open fashion. I chaos orb'd through more walls that I could possibly imagine, and I did it right in front of the very players that hid behind them. I was told it was legal, so I did it. And I didn't stop until I was told that I couldn't do so anymore.
I miss the ability a bit, but even when the skill worked properly, I felt as though it wasn't strong enough. The projectile speed was far, far too slow, and the distance was so pitiful I actually laughed for a good 10 minutes the first time I used it. It had a unique "raiding" utility, but as far as combat was concerned, it was an unreliable piece of garbage that never actually landed when you really needed it to.
So, how do we rework this ability? What should it do? Should it be scrapped until Ender Pearls are re-enabled? Should it be left as is and a completely new ability replace it? I don't quite know. I'd like to see some feedback on this from the rest of the balance team before I talk anymore about it.
4. Rebalance Wither
Wither wither wither. I have a love / hate relationship with this ability. Due to the minecraft mechanics I've mentioned in my suggestion post, Wither basically grants complete immunity to all melee damage while it ticks on a target. This means that whenever a Pyromancer uses Wither, he is forced to rely completely on his spells in order to damage the target, as his axe will connect once, maybe twice, during the entire duration of with Wither effect. Even still, I don't think it's a good idea to remove this ability from the Pyromancer. I think it's possible to integrate this awkward mechanic into the Pyromancer skillset without completely destroying it.
So here's what you do.
First, reduce the cast range on Wither by 1-2 blocks. This prevents it from being used purely as a "kiting" ability. A Pyromancer will no longer be able to spam wither / fireball / blaze and run in circles while he runs at a safe distance. If he wants to wither, he should have to be close. The Pyromancer is a melee caster--force him into melee.
Second, increase the damage. Make it a crucial part of the Pyromancer's skillset. Sure, they could "not" use wither, but they should be forced to make up for their lack of withering with something else. It will be impossible for the Pyromancer to deal any decent amount of Axe damage while the withering effect is present, so it's important for the ability to deal damage on it's own.
And finally, reduce the duration. It should be a "short burst" of damage to an enemy. Don't force the Pyromancer, or his target, to be locked into a witherfest. The Pyromancer should have an opportunity to deal axe damage when he wants to, and the target should feel as though a powerful ability has worn off and that he is now able to react.
5. Reduce Their Axe Damage.
With an increase in effectiveness of their withering ability, and an additional ability behind their belts to aid them in melee combat (Curse), it's important to not let them keep too much of an edge here. The bulk of the Pyromancer's damage should come from his abilities--not his left clicks. Reducing his damage ensures that he doesn't have such destructive power against light armored classes, and still stands on the same level as the other melee.