Not a counter point, but just to clarify: you can still make a custom character, just like DOS2. The origin characters are just if you want to experience a more personalized story. I'm not sure which I'll go with, honestly. I want to make my current D&D 5e character from a tabletop campaign I play with friends (a white Dragonborn Warlock), so I'll probably do that, but we'll see what the other origin characters look and feel like.
I like the existence of the Origin characters if for no other reason than they can join you as companions if you don't play as them personally. And there are more to come, so your pool of potential party members should be quite large, hopefully on par with the older BG games (or at least as close as you can get with full mocap and voice acting for each).
I disagree with you here. It wasn't balancing that got him killed, it was bad luck. He lost multiple 90% and 75% rolls on his first try, and even critically missed one of the 90%s. If he'd landed all or most of those, the fight would have been ridiculously easy. He also misclicked a couple times and didn't move his party members to a safe location when he should have. Basic D&D 101, and even basic Divinity OS 101.
Also, I'm totally against removing RNG. Dice rolls are core to the experience of DND for me, and games of this nature.
Also important to understand that, in DND 5E, both you AND your enemies have very little health early on. You can get KO'd (not necessarily killed, it's pretty easy to avoid dying in 5E) in a few hits because you only have 10-15 HP (which is about what the PCs had in this demo). However, the enemies also only have around that much HP. One of the brain creatures died from a single 15 damage hit, and that was probably overkill and not exact damage.
Well, I mean, some enjoy the possibility of getting party wiped every combat encounter due to "luck" but I certainly don't and I've played plenty dnd inspired games that featured dice rolls whithout going overboard on the bad luck consequences. Plus, you know, he kinda did say it himself..