For me, a key criteria for more content is online accessibility. If
Home | Level Up has lists that you can sort through for Heritages, Cultures, Classes, Feats, Spells, etc., like
https://5e.tools/ then the additional content becomes much more usable.
As an example, the spell list search capability on
Home | Level Up is quite good, but could do with a bit of enhancement. I'd like to able to sort for spells that do not have somatic components, or that have neither somatic nor materials components. Likewise, I'd like to be able to find Heritages or Cultures that give either armor proficiency, or natural armor.
If it is not searchable, then the more content that is published, the smaller the portion that is easily accessible, but I'm not sure how best to monetize this (at least to pay developers and the folks helping put the content online) while making it all accessible online. Have some subscription or lifetime fee to access it all online?
There also needs to be an easy mechanism to give feedback and point out errors to have them corrected fairly quickly. I've found a few typos in the Adventurer's Guide (e.g., the short description of Mirror Image under Warlock on page 285) and
Home | Level Up (e.g., the range of
Gear Spider's ranged attack is not 5' - it should be 20/40).