Quick mini-review: I was really intrigued by the idea of this, since I recently got The One Ring and felt it was a little too mechanical for my tastes and wanted something lighter. Wilderlands isn't that thing, for me, but perhaps it will work well for others.
The game as a whole is very combat oriented, probably 75% of the rules text is devote to that, and it turns out "songs" are basically combat-relevant spells. Characters really are most defined by their combat abilities and weapons, in spite of a brief OSR-y note about problem solving and avoiding fights. I felt like the social coming together aspect of both songs and Sagas (which are literally described as "abilities you find") was really missing, though the random encounter lists have some nice social encounters on them. That said, I did like the art and production, and the whole thing was very easy to read and follow, and I'm sure it would be easy to implement all the rules in play and find exactly what you need in the booklet.
Anyway, if you're looking for a general OSR-ish game with a slightly less "unhoused treasure seeker" vibe, this might work for you (though it's possible you already own such a thing). If you're looking for a "The One Ring"-type game with some lighter mechanics, this may not be what you're looking for.
Thank you for taking the time to review Wilderlands and leave such a well thought out review! I think you did a great job highlighting where the book focuses on and what it 'elides' for the Game Master to decide upon. I personally love when a book gives me more options and guidance for combat as a Game Master, as I don't like to try and figure out combat buffs on the spot when I am running the game - this saves me brain power for what I love to do, roleplaying out social encounters and problem solving, leaving combat to be decided by the dice. This is why Sagas and Songs have so little guidance on when to bestow them - other than specifying you learn them by helping others, it is totally up to the GM to based on the size and scope of their campaign how and when to award them.
If you are looking for a gaming experience that is more like the One Ring mechanically but highly streamlined (including a simplified version of the dice mechanic) I recommend Ever On by Logen Nein - https://logen-nein.itch.io/ever-on-2e - I hope you find the Middle Earth game that speaks to you!