So I've just listened to the yesterday's episode and have three point:
1) as the Tolkien Professor stated the wedding of B&L itself is not a huge event as they are a "done deal" by now - Thingol is just aknowledging the fact and the unavoidable - as such how can this be a "redemntion" for him - he just proves he is not completely an idiot - and we have known this about him already
2) The Tolkien Professor wants Luthien completely in her confort zone before she meets Beren - but then her meeting Beren would be an tragic event - as she was compeltely happy as she was and what Beren brings her is alienation from her family and people, struggle, suffering and death in the end. Sure, she acomplishes a lot and grows a lot - but if she does not personally care about neither acomplishment nor growth what is all this for her? What she gains would be only romance for a couple of decades, and that she could have head for much longer and deeper (as elves do bond deeper than humans do), had she chosen someone more suitable.
I am of the opinion - if she does not see it herself that she is "wasting time and potential" - than the audience should.
If all elvendom is so in awe of her but she is not really doing anything she is just a "celebrity" - "famous for being famous" only.
She seems so selflessly immersed in her art that she does consider the whole world to be just her audience, as such she does not notice neither Daeron's nor other peoples concrete needs and interest in her. But ironically this makes her also completly egocentric, stagnant and in the end actually meaningless - far more "form" than "content".
Maybe it is Melian who is worried by it. She sees her daughter stuck in the pursuit of her art - like a workaholic who forgets to "live" Luthien seem an "artaholic" - she forgets to grow as a person. [We all know or have heard of artists who neglect and sacrifice everything else for their art, friends, families, duties, own health and even life sometimes - nothing else is real or matters to them). Maybe it is Melian who tries to draw Luthien's attention to the fact that she is harming Daeron - not against his will - but still - as she seems to "lead him on" - and Luthien cannot grasp what Melian means, as Luthien's focussed is on her art, not on the people around her, who are just "audience" - like the trees and flowers in the forest.
Maybe Melian tries to interest Luthien in something else also, tries to challenge her (here the spinning wheel would come in) and Luthien is not interested at all - while polite to her mother.
Then Luthien's sending the request to her mother to send her the spinning wheel while in the treehouse would be a symbol that Luthien leaves this self- and art-centrednesss behind, now she wants things done, not "just" being "artsy".
This way meeting Beren whould be a gain for Luthien as a person, and not only an overpriced romance.
3) The tree house:
As I do not know what exaclty the Tolkien Professor's problem with the treehouse is, I do not know if this solves any problem he would have,
but the tree itself might be semi-sentient guardian - maybe a hald-awakend tree/huor but good-willing - and friends to Thingol - and Thingol entrust his daughter to it to guard her for him - maybe that tree comes to a conclusion that Thingol is doing wrong by "not letting his seed fall to the ground" as a tree would - as such deying its purpose - as such the tree would allow her escape?
But I am not sure if we have time enough for this - while it might give us some intersting special effects - a kind of a reverse "Old Man Willow".
As such the tree would witness Luthien coming to a decission, taking efforts to prepare her escape and in the end let her go - as Luthien would not harm the tree by fighting it, I think in the end it would have to be at least compliant. And the good thing is, Luthien would be able talk to it at times or partly to it and partly to herself.
Edit: Maybe Luthien's witnesses the tree letting her acorns fall to the ground - as she asks it/her whay does it/she not let her down also -and it/she does?
There is another question:
Seasons:
We know Beren sees Luthien in summer, and really meets her next spring.
Do we keep that? - What other seasons follow form there - which event takes place in which season? - We would need to figure this out.
Not necessary the moon phases ( 😉 ), but the seasons at the very least.