DISCLAIMER: So yes, I'm totally writing a revamp-ish topic for every class out there.
THEREFORE, my suggestions may in no way represent the original developers' sights on classes, but hey, if they made Zerks that imbalanced, I don't really trust them with the balancing anymore. Sue me. Of course, I'm not thinking I know better than anyone does, but these are MY suggestions on how to make the class[es] more in-depth and interesting. Feel free to implement them selectively, or not at all.
Addendum: I'm still Russian, so there are still occasional grammar/spelling mistakes.
--------------------------------------------------------------------------------------------------
Hello everyone! Fistand is back on the line.
As you'd guess, today's topic is Sage class. I'd like to remark right away that Sage is not that much underpowered as some classes[sub]*cough*Knight*cough*[/sub] out there, but they do have a sizable potential that's left unused, because their main weakness - terrain-dependence (circles, anyone?) is not properly outbalanced. They remain potent healers, but their main feature that distinguishes them from Priests is grossly underpowered, and this must be fixed.
(I'll run ahead and say that I'll be soon writing a thread for Priests, too, so don't yet bother comparing them.)
---------------------------------------------------------------------------------------------------
Alright, we're starting!
The main role of Sages in the party is to heal, buff and cure debuffs, much like the Priest. What distinguishes them from Priests is that they're able to do all the above on groups of people without experiencing frustration from healing everyone manually, as Priests do, which saves a LOT of time, nerves, and mana, The ability to mass-cure debuffs is often invaluable.
That said, however, Sages' ability to heal singular targets is impaired. They don't have powerful single-target heals like Priests
, and the main way Sages heal people is regenerative and delayed spells - meaning, they don't take effect immediately, which makes them far worse in inevitable "OH SHI~" situations - Priests are suited for this much better.
Moreover, Sages are very terrain-dependent. Most of their key features come from "circles" which are impossible to move once set, so it's hard to arrange positions in both PvP and PvE.
As you can see, the drawbacks are pretty considerable and they need to be outweighed.
So, let's get down to brass tacks.
---------------------------------------------------------------------------------------------------
I won't dwell much on their DPS capabilities, because they're obviously not made for that. However, I'll make one suggestion here.

1) Destructive Incantation.
Cast time reduced to 1.7s.
---------------------------------------------------------------------------------------------------
I will neither stop on their healing abilities, because they're pretty much balanced as they are. However:

1) Forceful Rescue.
[All Defense Power] + 1000/2000/3000/4000/5000 for 10 sec.
--------------------------------------------------------------------------------------------------
Moving on to terrain-dependent spells. This is where the majority of changes must be made.
1) Hallowed/Enchanted/Nullified Ground.
Remove the shared cooldown, but increase the cooldown of the spells themselves to 45 sec.
Why? Shared cooldown is the scourge of many Sages, becuase often in PvE and especially in PvP the enemies vary their types of debuffs. The ability to only dispel one type of debuffs, albeit over an area, severely impairs Sages' ability to support.
2) Devine/Moonlit/Pyre Sanctuary.
Remove the shared cooldown, but increase the cooldown of the spells themselves to 60 sec.
Increase the scope to 4.0m.
Devine Sanctuary: Every 3 seconds [HP] +5/7%.
Moonlit Sanctuary: Every 3 seconds [MP] +5/10%.
Pyre Sanctuary: [All Attack Power] +20/30%.
Why? Because all the spells require one to stay in range, which is usually a vast disadvantage in both PvP and PvE.
3) Celestial Sphere of Life.
Delay reduced to 5s. Cooldown increased to 30s. Heals a percentage of one's HP, not a number: 30/40/50/60%.
Upon trigger the affected people gain: [Damage Absorption] +50% for 5 secs.
Why? A powerful backup heal with it's own drawbacks, the main one being dependent on location and the delayed effect, thus requiring the Sage to carefully observe the situation and predict the probable harm.
4) Pillar of Life.
Lasts 30 seconds.
Effects: Every 1 second [HP],[MP] +5%, [All Debuff] Immunity, [Knockback] Immunity, [Damage Absorption] +100%, BUT: [Physical Hit Chance] -1000, [Magical Hit Chance] -1000, Every 5 seconds [HP] -10 (no cheating in Flag Matches!)
Why? It's a Sage's "ultimate". My opinion is that a Sage should be able to create a sort of a "sanctuary" right on the battlefield, enabling his party members to temporarily withdraw and come back with all their forces replenished.
However, attacking from such a sanctuary would surely be overpowered, so I cut this off.
--------------------------------------------------------------------------------------------------
Last but not least are the buffs.
I wanted them to matter more, since right now they're mostly negligible, except for Bestowed Agility.
1) Natural Power.
[All Defense Power] +500/1000/1500/2000/3000/4000/5000/, [Size] +20/20/20/20/30/30/30%.
2) Potential Growth.
[All Stats] +20/30/40/50/70/85/100.
3) Sacred Prayer.
[Heal Recovery Amount] +5/7/10/15/20/25/30%.
4) Ancient Knowledge.
[Maximum MP] + 500/1000/1500/2000, [Intelligence] +10/20/30/40.
5) Heavenly Wisdom.
[Maximum MP] + 500/1000/2000, [Intelligence] + 30/40/50, [Wisdom] +30/40/50.
6) Celestial Shield.
Increase the cooldown to 1 minute.
[Number of Protective Shield] +3/5/7, [Value of Protective Shield] +2000/6500/10000.
Why? Sages have 2 "shielding" skills, while Priest only has 1. This shield, however, should still be buffed a little.
--------------------------------------------------------------------------------------------------
That's mostly it.
I'm not very pro with the Sage, so constructive criticism is greatly appreciated.
This suggestion is aimed at making the Sage better suited for mass battles, especially PvP ones.
I probably took too much overboard with some "circles", but let's not forget that they're not too big, and in PvP any class with a knockback [sub]*coughWarlockcough*[/sub] can turn this advantage down. They can't be moved and have lengthy cooldowns, too, which is a severe disadvantage in tense PvP. Sage is more of a defensive healer who really is able to literally stand his ground.
Please comment!
Fistand out.