Comparing the Ranger to the Rogue is a fair comparison. I actually tend to make that comparison myself, and am sad they went the "warrior" rout for the Ranger.
So where does it stand? Lets just look at pure damage, without to hit chances. Both are TWFing shortswords.
1) Ranger 2d6+3 (10), Rogue 3d6+3 (13.5) = Ranger -3.5
2) Ranger 4d6+3 (17), Rogue 3d6+3 (13.5) = Ranger +3.5
3) Ranger 4d6+6 (20), Rogue 4d6+3 (17) = Ranger +3
4) Ranger 4d6+8 (22), Rogue 4d6+4 (18) = Ranger +4
5) Ranger 6d6+12 (33), Rogue 5d6+4 (21.5) = Ranger +11.5
7) Ranger 6d6+12 (33), Rogue 6d6+4 (25) = Ranger +8
8) Ranger 6d6+15 (36), Rogue 6d6+5 (26) = Ranger +10
9) Ranger 9d6+15 (46.5), Rogue 7d6+5 (29.5) = Ranger +17
11) Ranger 9d6+15 (46.5), Rogue 8d6+5 (33) = Ranger +13.5
13) Ranger 9d6+15 (46.5), Rogue 9d6+5 (36.5) = Ranger +10
15) Ranger 9d6+15 (46.5), Rogue 10d6+5 (40) = Ranger +6.5
17) Ranger 12d6+15 (57), Rogue 11d6+5 (43.5) = Ranger +13.5
19) Ranger 12d6+15 (57), Rogue 12d6+5 (47) = Ranger +10
This is ignoring everything else both classes get, yes. It's also ignoring that the rogue only has to hit with one of their two attacks to get most of their damage, while the ranger would have to hit with all 3. I'll run the numbers with a 65% chance to hit at the level 19 mark there ...
Ranger: 4d6+5 x3 *65% hit chance = 39.15
Rogue: 1d6+5 *65%; 1d6 *65%; 10d6 *(87.75% chance to hit at least once, 5.88% chance that the first or only hit will be a crit) = 41.1705
And TWFing wins on being awesome for the rogue. So it's not going to be a really big deal. Level 9 looks problematic, and so does Level 5. The rogue has some more stuff going for them. Good job on landing the end point pretty close!