1) Tooltips - the game needs a system that a) actually shows what kind of modifiers players are getting and b) has tooltips for those modifiers that explain what they are. This is implemented in some systems, but hasn't been implemented in some areas where those modifiers can get a bit convoluted and confusing.
Yes. Or at least have an option to switch to something more direct. I think Larian is trying to convey DnD mechanics, without having to worry about the specifics (hey, you have more or less that MUCH chance to hit. It gets influnced by those things by SOME amount) but I would rather see details. How much I need to roll to hit. What modifiers exactly are added. At the very least the combat log needs to be better (see: Deadfire). I would prefer, to cut out the middle man - I dont' want the "Larian layer" which uses familiar XCOM-like UI elements to transalate to me completely different mechanics.
2) An option to flip open the BG3 version of the Player's Handbook and see why things happen the way they happen. Basically, give us an in-game encyclopedia. Sure, a lot of players don't use in-game encyclopedias (and they're the ones who will need tooltips), but some players would definitely benefit from having a feature like this.
Yes. Or at the very least attatch PDF Player's Handbook in game files. BG1&2 had those and they were very helpful.
As for the tutorial on the ship, I have wondered about that. I am suspicious of it. I wonder if they are gonna pull something like, "Hah! We didn't really give you a backstory because you ARE the Absolute." I mean, unlike a lot of D&D video games, they don't even give you a space to write your own backstory. Hmmm... Makes you wonder, right?
Nope, D:OS2 works exactly the same way. And all the origins do have fleshed out story. It's only custom character that is devoid of character development and that's because unlike PoE or KOTOR2 game isn't designed with custom character in mind, so we don't get a sequence when we can define him/her. You pick an origin, or you play as Mr(s) Blank.