I love Babymetal. The Kami Band are great musicians, top of the top, some of them even play and arrange songs for their albums and Su-Metal is a great singer, I could do without the other girls' "singing" but it's not a dealbreaker, it's charming for some songs and they are just a super fun band. Also, their song No Rain No Rainbow is also a tribute to Endless Rain and Say Anything, in this performance they even have Yoshiki's Kawai crystal piano on stage and they are wearing neck braces while "playing" it.
Other tributes to X is the "We are... Babymetal" thing they do and the neckbrace thing they wear in a song called "Headbanger". Yoshiki joked about their collaboration last year during a Q&A in Germany, he said he'd like to collaborate with other people but he will do after the X Japan album is released, someone yelled "Babymetal" and he said "but by the time the album is released they won't be babies anymore haha" I love that he can see the humor in this too xDD
EDIT: The first time I listened to Akatsuki I though "this sounds familiar" then the solo came and I was like "WTF This is Silent Jealousy" haha