I wouldn’t wait for another class to come along, as there are no publicly known plans to release one. However, the disparity has been known for a while, and recently was cemented with data (Data for Rebalancing DPS). I also discussed a potential way to close the gap between DPS classes, but that’s just me as a player throwing something and hoping it sticks.
The devs are aware of it and have said that they plan on balancing numbers in Q4 of this year. I’m hoping that with the data provided it helps bring things in line. I will say, though, that Ranger and Shaman are a bit different at level 30. You’ll notice a huge spike in damage, especially as a Ranger. I’ve seen individual hits for over 400k. Leveling and keeping gear appropriate to your level is the hard part. Once you hit level 30 and start getting end-game gear, you’ll be able to handle things as a DPS easier. Getting tilesets and a solid rotation will also aid in killing things quickly. Except for the Wastelands top level mobs, I find as a Ranger I can kill most things before they get to melee range with me. You’ll get there too, it’ll just take a bit more time.
A quick note, you’ll be pulling easily more than half of Mage DPS with any of the other three classes 90% of the time. Very few mages are pulling extremely high numbers. Unless you’re dealing with the top players in the game, your level 30 Ranger will be just as competitive in most content.
Best I can say is try and max out the class you enjoy. Everything is viable at end game right now, even if it’s not balanced properly. I know it’s frustrating that the numbers gap is the way it is, and it may feel like you’re not getting the most out of the game because of it. However, I’ve played every DPS class in Shard 15s and Hard Mode Raids with great success. It can be done, and even if you’re not the top DPS as far as numbers goes, Ranger does bring great spike damage and a great armor debuff to enemies. Enjoy what you can, and know that good things are coming soon.