I'm assuming in gm mode you can create nps dialogue your own quest and actually play the campaign you create live with your friends with you as the gm etc a please tell me you can! ?
You may be assuming too much.
There have been some differences in opinion about what a GM mode should be. It's not entirely clear what Larian's vision for this will be.
My impression of Sword Coast Legends is that it wanted to turn being a GM into a game against the player. An asymmetrical battle of wits. I am hoping Larian does not emulate this.
I am hoping Larian tries to create an experience as close as possible to the established role of the GM in existing tabletop games such as D&D (ie, as a storyteller/facilitator).
Of course, I'm not in charge. Feel free to suggest any other features you'd like to see.
That's ultimately what I want to to tell a story in game I've made as gm while occasionally stepping in the role of fate /the God's etc to increase the challenge