Adding Feats to 5e Backgrounds
Spelljammer’s errata says that every player should start with a Feat. With that becoming the new norm in 5e D&D you shouldn’t limit yourself to the three suggested Feats.
Unearthed Arcana expands playable dragons – lacks playable dungeons
I like most of the story behind the new Draconic UA, and only see need for a couple tiny tweaks.
Full Moon Storytelling 