The actual balance state (on a PvP shard, but taking PvM into account to level).

Mages :

Advantages :
-The class with the highest possibilities when fully buffed.
-The best XP rendering in the 35 to 65 levels
-Drain and heal spell without having to switch weapon
-If you hit, you deal 90 to 120 hp damage on a guy buffed and vulned with VI
-You can pretty much solo any creature in the game with a decent template

Problems :
-Hardest class at low levels
-Most expensive class in terms of credits because of the need to have the 4 school, and of course the insane cost of WAR.
-The casting time of spells and the speed make them pretty much useless against a player with minimum experience and lower the real damage dealt to something quite uneffective...
-The max war damage you can do on someone in 1 spell is between 90 and 120 hps if he's not buffed.
-Mages are the most expensive class to level due to poor loot on their main target (tuskers) and excessive cost in regs.
-The fun factor of mage is lowered by the boredom of ubber buffing.
-Stats are ok to set bu hollow patch + reg burden forces to set a rather high strengh.
-Reg shopping way too frequent and boring due to high burden and the interface...
-A mage can't kill a target that runs / doesnt want to fight.

Archers :

Advantages :
-Easiest class to level from 1 to level 30
-Skills / stats templates are the easiest to set
-Benefits from the coordination correspondance between bow, melee def, and weap (specially dagger).
-High loot on olthois
-Low cost to level
-The Class that can deal the biggest deal of damage ever.
-Archers can 1 shot unbuffed peeps
-You can pretty much solo in creature in the game with a decent template (specially with the accuracy bar)

Problems :
-Fighting a full buffed Mage in GSA with the 5 pieces baned / impened VI, armor VI, and prots VI, that you Imperiled VI, vuln VI, you do 10 to 15 hps a hit
with 30 hps crits.
-Rather good xp rate till about level 40, then the rate lowers since you have to switch weaps to imperil and then equip again to kill.
-Melees are a pain both with their shields and attack if no md.

Melees :

Advantages :
-Not too demanding on skill credits
-Pretty decent xp with little problems when fighting golems / olthois which makes leveling not that hard in the 1 to 30 area.
-Great loot from the olthois
-Very little damage with the evades / and mostly the shield (0hp to 1 hp damage crits when buffed)
-Cost is quite ok being between archers and mages on the cost (mostly potions, kits and mana stones).
-Best class to use when leveling from 50 to 100+
-Hollow weapon is devastative, can even give 45 hp crits to peeps wearing GSA, ot helm and 120al gloves and solerets...

Problems :
-You're forced to make some choices on your stats.
-Less effective at leveling in the 35 to 45 area.
-Got to get close to your opponent

Mage vs Archer

Basically a Mage has great powers but the fun factor when it comes to reg shopping / buffing is rather low.
If being fully buffed with all the 7 banes VI +impen VI on the 5 peices of armor + the 7 prots VI and armor VI lowers the damage from an archer to 13/15 hps with 30/35 hps crits when Imperiled and vulned VI, forgetting or loosing one bane will mean that you'll take 30/35 hp damage and 60 / 65 hps crits which at the speed of an arrow means death.
On the other side it is very difficult for a mage to actually kill an archer due to the easy dodging of war spells, and the general speed of archers...
Nor does he need to stay in drain range to fire arrows on you...
If a mage is not properly buffed his chances to escape are pretty weak, while a mage can't kill an archer that doesnt want to fight.

Mage vs Melee

A well built melee is prolly the most effective char when it comes to PvP in average conditions, and even more in group fightings / PKing.
The hollow weaps, and most of all the hollow katar make melees become really powerfull even against a mage that has a fully buffed gsa.
The melee takes quite a lot of risks since he has to be in contact with the mage and thus is more vulnerable to drains/war spells. But war spells are so slow that any melee with skills can break off the attack as soon as the mage starts casting, to immediatly come back to the contact of the mage and deal more damage again.
Sticky melee is rather simple : if the mage is in a position that tends towards a loss, sticky melee will do the rest to make sure he dies.
While a mage can't kill a melee that doesnt want to fight.

Archer vs Melee
Thats prolly where the unbalance concerning archers is : If they got melee defense they are pretty ok but without it they're dead meat.
Even with melee def, an archer will still have problems against a melee due to the shield coverage. He can try to britmail the sheild and imperil / vuln the melee. But then
chances are that either the melee will run off screen, or the archer will have died while casting due to the loss of MD caused by the wand...

If archers needs some loving its certainly not against mages, but more against melees.

Affecting the balance between mages and archers would pretty much destroy the mage class for good...
Giving better way for archers to make xp could be a solution too, but imo, the only way would be to put pits such as the BDC one which is a bit against the direction devs choosed.