I can see the Pacquiao comparisons but beyond the speed, and work rate I think they are different fighters. Certainly early Pacquiao was more of an athletic brawler, he's become more refined but in terms of technical skill Lomachenko is a cut above.
For me Lomachenko is the king of the feint. He feints with his footwork, he feints with head movement and he feints with his punches. He is constantly feinting and it bamboozles his opponents. Even when he is throwing actual punches he'll often throw rapid but relatively light combinations just to distract his opponent so he can move to a better angle and hit them with a heavier shots. His ability to angle off is only matched by Mayweather.
For me he's p4p best only behind PBF, Rigondeaux and maybe Ward. He really doesn't do much wrong technically, as well as having great speed, great timing and fantastic movement he has a tremendous work rate. For me he's like a cross between PBF and Manny just without Manny's power but he still hits plenty hard enough to hurt his opponents.
I don't think he'll have any trouble with conditioning in the pros he's one of the fittest athletes on the planet. I've never seen even a hint of him getting tired. He really doesn't seem to have any weaknesses. His defence is great, his offence is great, seems to have a good chin as far as we can see at amateur level and he has great speed and conditioning. He could hit harder but that's about all.