1. The main story ends up being not very good. So far I think it is solid, but unspectacular. I found the beginning of Divinity: Original Sin 2 to be much more gripping. I honestly hope they add a prologue where your just play in a little town or something before your character is snatched up to give you more of an attachment to them.
2. That Act 2 and 3 are not nearly as big as Act 1.
3. That the city of Baldur's Gate ends up being as underwhelming as Arx was in Divinity: Original Sin 2. I would prefer we get rushed to a massive Baldur's Gate rather than the journey taking forever and Baldur's Gate being underwhelming.
4. That Act 2 and 3 are 'rushed'. Divinity 2 was great, but it felt like they ran out of steam by the end of the game.
5. That companion stories will end up dominating the game over the "main character's" story/journey.
6. Itemization ends up being lacking. I thought Divinity 2's itemization was great - but the pacing of it ended up being rough (needing to upgrade basically every level later in the game). I find Baldur's Gate 3's itemization to be pretty bland so far... but that might just be an outflowing of the D&D ruleset and its limitations.