We have no idea what those consequences are or how deep, if any, as far as the Illithid powers are concerned.
What we do know is that a lead dev stated the Illithid power skill tree was designed for high level progression. Gameplay. And no one is asking to be able to save scum important decisions, no idea why you brought that up. Far reaching consequences are expected.
The concern here is basically that systems devs are leading the game instead of writing, and the story and overall quality of the game will suffer because Larian is too much systems first, story second.
Come on now...you surely don't expect them to just lay out all of the spoilers and paths. But there WILL be consequences, that you can absolutely count on. The game has over 175 hours worth of cutscenes to account for very wild story permutations. You can't seriously complain about the lack of consequences and then backtrack to "well they haven't shown them so there might be none" given everything we know about this game. This game will easily and by far give the players the most agency over the story than any other RPG ever made. You have the freedom to do A LOT of things and those will lead to wildly different consequences.
