A lot depends on if you are Powerleveling to 70 for some reason...or playing the game for the fun of it. If you are PLing, it's probably a tie whether a Fury or a melee spec'd Warden will get you there or not. If you are in 'competition' with a DPS class to hit 70 first, then you will be unhappy.
If, however, you want to eventually be an end-game Warden, you'll want to stick with it and get the benefits of learning the class as you level up. I find I learn my capabilities best when soloing, and hate pickup groups. If you are playing to be an End-game Warden, you'll eventually have to know how to heal..and heal in a group. That's where what kind of damage you can/can't do won't really matter, IMO.
An Inquis can also solo and not die. Inquis DPS, spec'd for damage, is far better than Wardens'. If you are spec'd mostly to heal, you will also probably not die, but will lack DPS to do it in any kind of timely manner. If you are playing to have fun - who cares which class can level you fastest? Play what's fun. If you are playing with an agenda, do a risk/gain assessment and take the one that will -with your play style- level you fastest.