From thse clips, there's no way to know whether DSJ has poor landing mechanics -there's no information regarding his normal landing mechanics. What DSJ needs to be weary of, and this goes for any high leaper, is the risk-reward of leaping into traffic bc it's those unknown variables in the air that can really put you into adverse, high risk situations.

The higher and longer you're off the ground, the more risk you're at for contact and impairing your landing. The farther you have to come down, the higher the level of ground reaction forces (GRF) that your body has to attenuate upon landing. The intersection of impaired landing and higher GRF is increased risk.

The DRose comparison with DSJ holds in that both are under-sized high leapers but a major difference from what I have seen between the two is their movement patterns: DSJ is more of a straight-line jumper whereas DRose consistently contorted himself, impairing his landing even on plays where there wasn't major contact. Additionally, one of DRose's fav moves is the jump stop - which is high load movement - whereas DSJ, from what I have seen, tends to favor less jarring movements such as the 1-2 step, fake reverse turnaround jumper.