It varies by BG, but if you look at lan performance, WLD dominates. On live, with PvE gear on melees, the situation is a fair bit different, but if you look at numbers, PMR still doesn't compare to the druid based teams.

Keep in mind that PMR also has a few combinations that it just cannot beat ever - double healer warrior/hunter are incredibly rough. WLD is a horrible match up with undispellable fel armor.

Yeah, 3.0 is going to be the day of double DPS. I don't really think any team without a ret paladin can have serious success, but 3.0 is not really meant to be balanced, and Blizzard knows as much.

I am more concerned with balance at level 80, but trying to guess that based on short snapshots of people with vastly varying gear is kinda hard. Tipically though damage outpaces healing very quickly.

I actually suggested something similar in the beta forums a few days ago - I think that this would be a good way to partially protect mages/priests without having to give priests the ability to remove poison if they feel strongly about not wanting them to be able to. The issue with this, as you obviously recognized as well, is that pw:s/barrier would get eaten through so quickly if they were being eaten up from both mana drains and damage - so they wouldn't end up feeling like they are absorbing much of either unless you are not being attacked.

Of course your suggestion to adjust the coefficient for damage->drain conversion would definitely be an applicable solution for this. Another similar solution would be to make all mana drains deal some amount of damage, and require them to deal damage in order for mana to be drained. This would end up affecting priests/mages similarly, as you would obviously still use barrier/pw:s to prevent yourself from taking the spells damage (thus preventing the drain as well).

Elendril - This is not a problem that only mage/priest deals with, it is just as gamebreaking for other priest/x (and to a lesser extent mage/x) teams as well. If you cannot achieve a kill very quickly, which is difficult even if the priest is shadow against experienced opponents, you cannot win.

Amera - Priest representation is really not overwhelmingly high - for instance they are tied with shaman as the 6/7th most represented class in 2v2 above 2200 on US-Bloodlust. The reason priests have as much representation as they do is, as you said, obviously the result of their strong offense, which has been all but killed in wotlk with the poor scaling of mana burn and the extremely high mana cost of dispel. As it is on live, priests lack of sustainability is compensated for by their offensive power; in beta, this compensation is very weak by comparison. Also, while you have a point that hunters are less represented than priests, it seems very silly to me that hunters can have so many of their issues ignored based presumably on the sole fact that they can farm priests teams via viper sting. I imagine hunters would support a nerf to viper sting as well if it meant that their other problems were properly addressed :p

If I implied that mana burn was a terrible ability, that wasn't my intention. What I meant was that mana burn was an ability that required setup, and particularly, the cooperation of your teammates. If you end up fighting a 1v1 in an arena, mana burn will be of no use to you because you have virtually no ability to get someone to eat one. In other words, it's a powerful ability that requires a lot of effort to use successfully. The fact that eating mana burns was (as of 2.4; I haven't tried in 3.0) really, really bad contributed a great deal to its deterrent effect. Priests ARE a terrible class if you can't seize and maintain initiative, and mana burn was one of our main tools for accomplishing this effect. If you reduce the effectiveness of mana burn, aggressive strategies will become less risky against priests.

Well, another alternative would be "lengthens duration after dispelled" as part of the talent. For example: you dispel freedom, and it lasts 3 seconds after that or until it's duration expires, whichever is shorter. It would eliminate the RNG resists and give a predictable buffer to certain things. They would need to flag a spell as "dispelled" so you wouldn't waste mana trying to dispel something that was going away in another second or two, which might be a big coding project.

I think realistically you are much more likely for them to go black-and-white, a la fel armor/frost armor because it is probably the easiest thing to do at the coding level. But without a lot of thought put into that, yeah, you could end up with some really imbalanced situations. Ideally I think dispels are supposed to be another nice bonus of bringing someone along, not a requirement. But obviously in TBC arena that wasn't the case at all.