I only ever tried it once. I was completely absorbed for weeks and easily played 100h but then I just couldn't go on anymore. Like a lot of open world games with a huge amount of content, playing the game is more fun than actually finishing it. I'm pretty sure I was mere hours away from the end, I just had to clean up the rest of the last area a bit. But it was really fun and I don't think I missed out on anything since I basically got 99.9% of the experience. Wasn't the first or last open world game that I did not finish.

I think the chances of me not finishing XBC2 either are pretty good.

I finished the game on my second run. I was too weak to defeat the final boss on my first run and moved over to a different game. Some months later I picked the game up and did a proper walkthrough. 

Did you at least watched the ending on youtube?

Nah. It's an open world game, I couldn't give two shits about any kind of story. Right now I'm trying really hard to remember a single open world game where I did care about story but nothing comes to mind. I did care once in Assassin's Creed for the future story but they totally butchered and removed it, so nothing there either.

Watching the ending now wouldn't do anything for me either, now that I forgot most of the story and characters.

For skill trees, begin with Prudence because its first skill boosts the length of Auras a lot. They're not so important because the game gives more than enough points to unlock all his skills.

Yeah, Serene Heart

His AI is ok. He isn't as good as Reyn at generating aggro (he gets better later when he learns Overwhelming) but I never had any problems.

Shulk's AI, on the other hand... just don't let the AI control him if you plan to do some serious fighting.

I'd pick Gale Slash because his other arts get extra effects when used after it, but it's not very important.

Use level 2 crystals. The gem you get will have the same level as the crystals you used or one level above it (you won't be able to do this until waaay later). Keep in mind that not all gems of the of the same type and the same level give the same bonus.

The armour.... oh boy. Let's say that the best is still to come.

How was your first impression about Satorl Marsh in the night?

When I used Shulk in my party I always controlled him so that he took sensible actions. 

Do your other party members get attacked?

In my replays, I typically used (Makna spoiler) Melia, due to her being incredibly monstrous with her magic abilities, and her AI is a little broken.

I remember using Dunban almost as much as Shulk, would basically just alternate them in reserve. I feel like Attack/Aggro/Healer combo always worked pretty nicely.

Also his Talent move (if that's what it was called) was kickass. 

Born in a world of strife! Against the odds! We choose to fight!

Man now I want to play a spinoff game about Dunban alone.