arashi will get #1 in their week, and ayu will get #1 in her week. honestly, there's no real reason to worry because ayu will probably get another #1 regardless.
and you can't expect a new studio album to be just as successful as a BEST album. they're both completely different. considering arashi's current popularity, maybe their new album can be 500-600k in total. but i don't really expect so much since it's an JE album and all. but we'll see! i expect the unexpected when it comes to arashi.