What's not working at all is that I couldn't decide anything anymore.
I just chose the option of let's have a party, but instead my romance ran into the shadows and someone made a half-hearted comment about it that pissed me off. I wanted to run after him - then the party will take place here - will someone get a keg of beer before Karlach goes to Avernus - Is there sun in the Hells?
But my Tav stood there emotionless. Others also said nothing and just stared into the area.
I was left frustrated and then everyone just, what, walked past Astarion? Even my tav?
I suddenly couldn't decide anything anymore - and my only decision - the party, um, no.
I was also left frustrated because the game decided for me that I want to talk to Gale and Lae'zel, but not Shadowheart, and that I want to run to Karlach, but not after Astarion.
Controlling the brain has no endings at all and automatically assumes you want to do it alone and continue the invasion.
As for DLC I'd like something related to Durge. Purge or take over the Bhaal cult, become the new murder lord, have companions hunt down "evil" Durge if they didn't choose to control the brain, whatever. Or a prequel where we steal the Netherstones with Gortash.
Though I hope they fix the obviously unfinished parts like Cazador's basement before doing any expansions.