This guide is from a p2p pov but I am sure it would also work on f2p.
First of all to really maximise the stats you need a working stat changer addon, as with 8.1 all items can now be stat changed. I've been playing on RU servers and using a russian version of the addon which works for me but not for others so if theres any english working versions of the addon its a must have.
Mage in 8.1 can potentially put out the most damage in single target and also aoe (both pve and pvp as ice) but requires some knowledge, will get to that later.
Builds
PvE Ice:
http://calc.alloder.pro/#m/fju360ri1g010…3o5g90e::13ydj3 - If missing locus rubys then take 1/3 icy flow slow rubys but they are important when you eventually unlock fabled sector.
Pvp Ice:
http://calc.alloder.pro/#m/fgu260rj1g030…o5g906::13ydj3: If missing locus rubys then take 1/3 willpower rubys.
Pve stats/tips
Consumables - Determination (Potions + rum)
Offensive
(Single Target): You will eventually be aiming for
500 double attack(120 guild ruby bonus),
174-190 Elemental Damage and all other remaining in
Determination, every other stat should be 0 other than the base 90 brutality from rubys. Early on with no legendary/fabled items, aim for 400 double attack and 174-190 elemental damage, rest in deter.
Offensive
(AoE): Stat choices are the same as single target
but you switch the 174-190 elemental damage to
Astral Damage. This is where the stat changer addon comes in handy for swapping from aoe to single target stats in seconds.
Defensive: You will eventually be aiming for 500 concentration, 250 bloodlust(120 guild ruby bonus) 100+ survivability and a item or 2 with vitality. Early on in non legendary/fabled gear around 350 concentration is enough.
Single Target Tips
To get the most out of mage single target damage, it requires applying a buffed up star shower debuff, which when applied fresh it stays at the same damage bonus for when it was applied to the target. It helps when your support in group knows how to maximise your damage, or just generally for trials etc its handy knowing how to get the most out of this dot.
The key to getting the most damage from this spell is to have Crow's(racial ability) Trinket proc, determination bar at 90+ and buffs from support, power + all stats at the time when you apply a fresh meteor star shower debuff, this is normally done at the start of every boss fight. There must be no star shower up on the target when you apply this fresh juiced up debuff, so be sure to use up any remaining star shower debuffs. After this you pretty much have to play around this strong dot and not let it fall off, using call of elements + the martyr ability if you run into a bad string of rng, you should not use those 2 abilities other than to help maintain your super buffed up dot.
Aoe Tips
Mage can put out the most ridiculous aoe damage with the right stats, when it comes to 2+ targets astral damage becomes stronger as majority of mage aoe damage is astral, meteor/ice flow(aoe component) electric shock (aoe component). Using the new Aoidos racial + faster speed casting 3min ability(forgot what its called in english), you can melt packs with overpowered meteors + ice flow but beware of overaggro! Its possible to out dps another mage using catalcysm with just meteor spam and ice flows with these stats. ( If you ever do use or are expecting to use cataclysm, use the single target stats, as cataclysm is elemental damage)
Pvp Stats/Tips
Generally i'd advise most mages to play fire as its easier and does more for the team but a Ice mage played properly and statted correctly, no other class can compete with its damage in pvp.
Consumables- pvp damage juice 10% + proficieny potions
Offensive: 500 double attack(400 at non leg/fabled gear), 174-190 astral damage, all the rest in proficieny. The thing that makes this build viable in pvp, no gear slot is a wasted slot when it comes to offensive damage, all other stats than the 3 mentioned should be at 0 (other than the base 90 brutality rubys)
Defensive: 500 caution(important to get top 100 in your order for the +100) all the rest in bloodlust/vitality.
This build even with the correct stats is squishy, so you always have to be careful and play from range, using invisiblity/flash to get away from any focus fire. I would not recommend this build in 6v6 Domi as you would need a very specific setup to make it work and also just fire is generally better all around in that situation.
Peace