I'm by no means proficient enough when it comes to guitar and music in general to judge, so I'm just dropping by to say I really enjoy reading your input, guys.
IMHO, I lean more towards the monetary/fan thing. Even if X Japan didn't earn anything from rubbing Hide's ghost in the face of each and every fan, his legacy works a bit like a magnet: selling more Hide = selling more X = more overall profit = more crying fangirls = more endless rain, etc.
Teemeah has a point too, though. Being Sugizo is probably not piece of cake. Hide had written his guitar parts himself and performed them a billion times (sporting a billion different haircolours and all kinds of impractical eye rings). Now exit the guy and enter Sugizo, who probably had very limited time to rehearse with all band members plus the occasional WTF guest guitarist. Yep, not easy. At the same time, this is a visual band, I wouldn't be surprised if Yoshiki's priority was the visual/grandiose aspect of it rather than impeccable sound. Hence the WTF guets guitarists, the Violet UK mumbo jumbo, the holograms, the like-sized plushies, the fireworks, the awkward on-stage hugs, the crying like a sissy instead of playing key piano parts, the passing out during drum sequences... it's showbiz my brethern, and our Supreme Leader Yoshiki is the master of showbiz.