Well, I still imagine they want Genie to look as close as possible to the animated version, but with Will Smith’s face. I don’t know... are they first to depict genies in that style? Like colorful humans with bigger builds than the average person? Either way, I can see why they didn’t want to deviate too far from that look. I do agree that at least adding the glow may have helped.
Sure, they could’ve done a better mocap and performance capture for it, but I don’t think Disney has cared that much to do so with these adaptations. At least, not for all of them.
And if they had actually made Smith wear blue makeup, I think people would still complain and still make comparisons to Arrested Development or Blue Man Group or whatever.