I think some people are forgetting what the actual purpose of a priest is. A priest is a support character in this game, not made to compete with other DPS classes. So, to argue that it's unfair because the support character would have a more difficult time killing end game bosses is just senseless.
One also might argue that Magical Soul is the perfect counter to high HP powers in PvP and for that reason it should stay. Well, in that case, aren't power types also a problem? No other class is able to wear 200k HP and almost 100% of the time 1 hit any other class. "theres only 2 differences between magical soul and tempest strike, the first one is soul is ranged, the second one is tempest does 20x more damage than a magical soul." This is an example of a comical argument. First off, tempest strike is an end-game skill and as such is used in end-game. Magical Soul, on the other hand, is a skill obtained when you begin the game, at level 1, yet it's still used at end-game. What other class in this entire game uses their beginner skill anywhere but in the beginning? None. Secondly, tempest doesn't do 20x more damage than magical soul, not even close.
PvP's community is pretty small as is, so it could only be 1-2 people that use bubble, but considering the fact that there are merely 2 opposing sides regularly, that's more than enough for it to be brought up for discussion. There being more people using it PvE is even more of a reason for it to be talked about. There are multiple ways the skill could be nerfed to where it's still viable in certain situations, however, the skill in its current state is not acceptable.
A level 1 beginner skill being an instant cast, no-cooldown nuke makes no sense in any way shape or form. The cast time could be changed to the same cast as Mana Arrow, that way there's some actual counter play to it but it's still a nuke, and it doesn't affect the beginners as it's a casting class to begin with. As a matter of fact, almost every other class'(if not every other class) beginner skill HAS a cast time, yet nobody complains about the difficulty in getting to the appropriate level needed for their next skill. If anything, this is a compromise, because what we should be asking for is for the AP ratio on the skill to be removed completely so that the skill is strictly used in the same way as every other beginning skill.
The cooldown could be changed, although if this were the nerf it received it would need to be more than a 2 second increase, considering the class who uses this skill the most is priest and they have Refreshing Dew. This type of nerf, however, WOULD directly affect the people the skill was actually intended for, you know, the beginners. Either way, it's not like that skill is actually used for more than 10-15 minutes after starting a new character, as it's so quick to level up early on, so the only people it would hurt are the ones abusing it.
I'm not sure if anybody has ever said that Dimensional Rift shouldn't be fixed, in fact I bet every single person who plays this game would be happy with it being fixed. So to attempt to redirect the attention to a skill that even the people who use the skill themselves(yes, you guys use rift too) would like to be fixed makes no sense.
The skill is not hard to pull off, it scales with MA as well as AP, even an extremely under-geared and poorly-compounded mage could manage to deal ridiculous amounts of damage with it. It's not about "how someone chooses to play their class," or how they choose to build their stats. It's about the simple fact that there is only one skill in this game for one class that is able to have so much utility despite it being intended as a tool for beginners to get to level 10.