Problems of Altaholic

[Vilgefortz]

Hello, folks.
I have a problem here, which at times can ruin the game experience for me. I really cannot choose the class I want to play, secretly wishing to bring them all up to 100.
Now I realize there's no way I'll be able to play all of them even in the best-case scenario, but it doesn't stop me from dreaming.
Mainly, I'm an Alliance player, but me and my gf recently decided to create a Horde alt to play with our friends.
I love the style and feel of blood elves, so it's a no brainer for me. But as for the class, I'm trying to choose between mage and priest.
On the one hand, I already have a lvl 90 Alliance mage and I don't want the gameplay to feel repetitive. On the other hand, I've never been into this whole healing thing (tanked my whole life, main is a warrior) and apart from healing priests look rather dull.
I really like levelling and I want to have each class to check them all out, but the amount of time it takes discourages me from even making a choice.
What's your advice and how do you deal with altoholism?

[Brewhan]

pick a class that can utilize multiple roles so you dont get bored fast (pally/monk/druid/) or healer/dps roles

[Lochton]

I'm a lost cause, already said that back in Wrath when leveling slowly turned easier and easier - I'm a lost son of Azeroth.
Trying to limit it myself but failing. Now I'm with "This is my main Horde... This is my main Alliance, this is my main Raider, this is my main PvP'er, this is my main RP'er, this is my main Achievement character, this is my main X profession".

[Nihilan]

I also have to level everything to max before i can see what i will be playing. Its been especially true in WoD due to how dramatic the L100 talents impact the play of the characters. Some of the classes have terrible, terrible L100 talents that make me not want to play them once theyve hit L100. (Mage, Warlock) To decide which ill be maining, I just ask myself which is my favorite tank? Which is my favorite healer? Which is my favorite melee? Which is my favorite ranged? The character i choose to pvp with will be on that list anyways, so i just focus on those four.

This xpansion its:
Dk - Tank
Druid - heals
Melee - There are no melee that i really care for this xpac, but i do play feral occasionally.
Shaman - Ranged (In addition to PvE, ive been PvPing as Elemental because i am apparently a masochist.)

(Hunters are fun, but theyve always been a dime a dozen at the best of times. In WoD its more like dime a hundred now that they are the only ranged with any mobility left.)

[Vilgefortz]

Hey guys, thanks for the replies.
I noticed that most try to justify their choice by class mechanics, which of course change from patch to patch.
For me these changes have become especially annoying, since I feel more and more discouraged by the current state of my warrior.
Back in the days when I started playing (WoTLK Naxx) it was a tough class to tank. Now I'm just plain bored most of the time and don't what to do, since he's been with me since day 1. He got all reps, achieves and I've simply alway identified myself as a warrior, my class in WoW.
And to throw it all away, in an attempt to find a more suitable class... man, I don't know. Feels like a betrayal of sorts.