Numbers may help clarify the picture, here. Compare second level non-crit damage potential (not expected DPR - we're looking at spike damage, and it's cold outside and I don't feel like performing that degree of number crunching) with other striker classes. Assume best possible race/stat spread, a relevant focus feat, and +1 weapons or inherent bonuses used with an at-will attack. Other feats and conditions are called out in the analysis.
Ranger: Twin Strike w/ Greatbow, target is quarried: 1d12+2 + 1d12+2 + 1d6 = 34.
Rogue: Sly Flourish w/ Dagger, Backstabber feat. Target is granting combat advantage: 1d4+10 + 2d8 = 30.
Slayer: Duelist's Assault stance w/ Fullblade, target is isolated: 1d12+14 = 26.
Warlock: Eldritch Blast w/ Killing Curse, target is cursed: 1d10+6 +1d8 = 24.
Now assume, for whatever reason, the conditional circumstances aren't met.
Ranger: 1d12+2 + 1d12+2 = 28
Slayer: 1d12+10 = 22
Warlock: 1d10+6 = 16
Rogue: 1d4+10 = 14
With conditionals in place, the Rogue still has a lower at-will damage potential than the Ranger. If the Rogue can't get combat advantage, it looks very sad indeed.
This is misleading.
First off, with the Essentials rules (or with Cunning Sneak or Flank or Cloud of Darkness, etc.), it's extremely rare that a Rogue (and especially a Thief) doesn't get CA.
In your first analysis there, the Ranger automatically hits twice (and I'm not quite sure how he gets an extra +1 damage, it should be +1 total for magic bow). And the Rogue is not using a short sword.
With a 50% chance to hit with quarry, the Ranger's dpr (+1 to the d12) is 10.675.
With a 60% chance to hit with CA, the Rogue's dpr (+8 to the d6, 4 for dex, 3 for cha, +1 for magic weapon) is 12.775. This increases to 13.1 if he uses Rogue Weapon Talent and a dagger.
So although the Ranger can hit twice in a single round (for an average of 18.5 damage when that occurs), the Rogue hitting once averages 20.5 damage. The Ranger would get more if he maxxed damage compared to the Rogue maxxing damage (32 vs. 30), but that is extremely rare and not worth considering. Most rounds, the Rogue outshines the Ranger.
If they do not have their conditions, then the Ranger does indeed get the edge.
8.05 vs. 5.875 or 5.85
But, looking at max damage if the attacks all hit is not a good way to look at it because the attacks are not always going to hit and they are definitely not going to be max damage too often.
And Essential Thieves blow the doors off of Rogues. They are a real DM nightmare to challenge the party without a TPK at low levels because they can often hit a foe for ~70% or more damage per successful hit.
The first level Thief in our game has almost single handedly wiped out all of the opposition in 3 rounds (4 on 4, plus action point, hitting every round) one encounter. The rest of the party helped, but he easily did 80% of the damage.