I think adding a section in the tutorial explaining how targeting works or making an advanced tutorial area with ideas like this would be helpful. To further elaborate, I mean explaining how illuvials choose a target. For example they look to the closest forward and then to the left or right. Kind of niche but can make a big difference for positioning if you know it will choose the left or right frontline assuming they are both equally close and for how they will choose the next target after one is defeated. Maybe too niche and just something players need to experiment out with for themselves but curious to hear what others think.
I would also like to see a tutorial in overworld related to fusing illuvials and how this works in detail. I think all the info is there but it took me a while to figure out you needed a certain amount of combined xp to fuse and I still am not sure if you can fuse with only 2 illuvials if the criteria are met but leveling up to test that. I also think adding in how stats of fused illuvials play a role in the created illuvial would be very helpful for players. ( I know you can search discord and youtube and find a lot of this however it helps to have it made simple for new players).
Finally I think a quick spin around the sanctum in the overworld tutorial would be helpful simply highlighting each podium you can go to and what they do. The fuse area took me about a min to find as I started on the edges and knew it was somewhere but not where. I could see new players not knowing they can fuse until randomly finding it or seeing a video or post. All that being said I think the team has really stepped up the game and it shows. The current tutorial is very informative and the game is looking amazing and feels smooth playing for the most part.