I bought the character manager a few days ago, and I'm pleasantly surprise so far. But I have a few concerns.

First, there's no support for Expertise. Perhaps there could be second checkbox after Proficiency. It would be grayed out and unclickable unless the Proficiency box was clicked.

Second, automating the choice of skills would be nice. I have an idea, but it would require altering the files of classes (and maybe backgrounds). The online class creator would have a new input: Skill Selections. This would be the number of skills that you are allowed to pick out of the list in the 'Class Skills' feature (Rogue picks 4, Monk picks 2, etc.) When creating a character, the app would scan the skills it has downloaded for ones matching those on the Class Skills list (These would be case-sensitive, with Perception different from perception). Then it would present those skills to be chosen by the player, only allowing the player to pick a number of skills equal to the Skill Selections number.

Third (and this is the tricky one), archetypes need to be improved. My idea is that classes gain a second new input: Archetype Selection Level. This would be 3rd level for most classes, 2nd level for wizards, and 1st level for clerics, sorcerers, and warlocks. When a character has this number of levels in a particular class, the app would scan its archetype files for ones matching the class (this would also be case sensitive, with Rogue - Thief being recognized, while Rogue, Thief or Rogue  - Thief (two spaces) would not be recognized). Then it would serve these archetypes to the player in a selection menu, and the player would pick one. This would then be added in an 'archetype' space in the same area as background and race are now.

Are these things feasible, or am I expecting too much? And if these changes were implemented, would people like them?

I have downloaded all the official material I can find, and some of my homebrew classes as well. But when I try to import my custom items, I get an error message:
Failed to import data.table item has no column named app_id (code 1): , while compiling: INSERT or REPLACE into item(id,name,category,subcategory,caster_level,price,weight,full_text,reference,aura,app_id) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,)

I'm stumped as to what is wrong.