I was worried when Wonho left Monsta X, because he worked on quite a few of their songs and because his voice was so distinctive. But I was happy to discover that MX still sounds like MX post-Wonho and I still love them. And now, even with Shownu in the military, I think their sound is still amazing and distinctively "them".
With EXO, they started with 12 and have promoted with as few as 6 and still sounded like EXO.
Do you think your faves would sound like themselves after losing a member? Two? Half of the group?