I Did expect it, i also wanted to fight Mishima's Shadow on the trip to mementos to find it.
but i also expected pancake boy akechi to have one, not a effin persona........
@Aphoria
I found this a few weeks back in a wiki fandom's page for him:
"Unused Shadow negotiation files in the game indicate that Akechi was intended to have a Palace at some point.[8]"
I found this in the trivia section although I do wonder why it wasn't implemented into the game.
Game was delayed multiple times. You can probably look this up more but it's likely the delays were due to a lot of changes in design.
There's also a lot off strong evidence Akechi wasn't even intended to be a villain and instead just outright be the last party member. This is linked to the fact that there's actually an empty space within the group during the final encounter.
There's more example of these last minute design changes but I'd probably start ranting about this and that if I got into that.