First let me preface the following saying I only talk about 2v2, as I assumed that's what OP asked about.
Actually, as someone that plays neither class, I can give you an unbiased opinion. Besides, using your logic, as you haven't played spriest, you would not be able to talk about them either.
Ignoring this logical fallacy, let's move onto a proper debate as to which is superior. Elementals can kite better, you are right. However, once an elemental is stunned, he is a sitting duck. Other than stoneclaw and thunderstorm, you are heavily reliant on slows. This is not ideal, as a) it leaves you extremely vulnerable to ranged classes (such as hunters), and b) leaves you vulnerable to classes with strong gap closers (warriors/rogues/dk's etc.). Everyone with decent playing experience knows that you cannot let an elemental free cast, so you can certainly expect to be trained in every match.
What does this mean? It means that the elemental is usually playing defensively from the start, using slows, totems, thunderstorm just to survive. You may get a flame shock off if you're quick enough before getting trained hard.
Now let's compare this to a priest. A priest will certainly pull a DP off to get their procs rolling. He also has SW:P on instant to get 2 dots on the go. If the priest gets rushed, he has a fear to drop the melee. If that fails he also has a disarm/horror ready. Assuming EVERYTHING has failed mystically, he still has a dispersion on the fly. Along with this, spriests have an instant bubble.
I never said elemental's are a joke in arenas, I said they are a joke to me as a hunter, and I totally stand by that, as elemental teams have been responsible for large rating gains for me :)
Now with all of that done, if you still think elementals are stronger than spriests in 2v2, you're welcome to your opinion. I personally detest spriests, and hate fighting against them. Statistics also speak on my side, as it is pretty well known how dominant spriests are in 2v2.
@OP: What you should really consider is which class you will find more fun. Due to spriests mechanics, they certainly are an easier class to master. However, this just means that elementals may provide you with a challenge that you will enjoy more. Elementals have possibly the greatest burst in game, and it can be very fun dropping enemies left and right in a BG. You can try both specs in a BG on the Blackrock realm to get a feel before making one a main.