Can you imagine going through the whole game only to have the MC wake up in a pod. A newborn Mindflayer. Its was all a dream ohhhhhh.
If played and writen in a masterful way that could be an amazing end.
Ohh how about this: you are actually the chosen Mindflayer of legend, but you retained the memories of the host, the created character. You wake with an army of elder brain at your command and you have to choose what to do next.
Then boom the one and only Ao himself shows up wrecks all your stuff, then tells you "you won't escape this time". Then you realize you have done this many times escaping to the past and renewing the conquest of the universe. Each time with greater consequence.
You escape again just barely and role credits. Then an ad preview for 6e pops up. Lol
I'm having to much fun. I'll stop.