I don't think anyone thought of him as a perimeter player. In his prime he was in the same class as Tikkanen and Claude Lemieux - elite pests with first-line offensive skill. Sandstrom was probably the most talented of the three, though.
His legacy would be better if he wasn't injured so much. 7 seasons where he missed more than 10 games, 4 missing more than 20. If he doesn't miss ~200 games due to injury over the course of his career, he clears 1000 points in all likelihood. He also had several seasons where he was on pace for 50 goals or 100 points, and fell short due to injury ... in fact every time he's having a huge season he has the misfortune of getting hurt. 40 goals in 64 games in 86-87, 89 points in 68 games in 90-91, 52 points in 39 games in 92-93, 70 points in 58 games in 95-96.
As for the original poster's question, IMO yes the Kings were better off from that trade. Sandstrom and Granato were outstanding for several seasons in LA, and both were huge factors in the 93 playoff run. Nicholls was very good, but I don't think his impact was what those two could do combined.