Possession: themes, ideas, weaknesses

Possession, as I seem to see in all reviews, is about possession in different senses of the word—possession, ownership, copyright; items, belongings; the feeling of possession that the biographer has towards their subject; the lover’s possession of the beloved, possession in the sexual sense.
What interests me more about A. S. Byatt’s novel is that it is ultimately about writing, reading, and interpretation, or misinterpretation; the difficulties in writing biography, and impossibility of truly understanding a writer, or anyone, through their writings and other people’s accounts; and the idea that you easily misinterpret things and form false conceptions of a dead writer when ignorant of their intentions and context. The story of Randolph Henry Ash and Christabel LaMotte makes you think about hidden clues and gaps of knowledge—once the academics discover the previously unknown truth about their connection and the Yorkshire trip, and know that they, in a way, wrote the poems for each other, everything takes on a new meaning, things that don’t fit now fall into place, all the theories are dismantled, and the 2 figures now appear in a completely different light. The form, the make-up of the book, in which the story is told through the 3rd person narrator as well as the characters’ letters, journals, biographies, literary criticism, poems… is a perfect choice for the subject matter and Byatt’s ideas. It works well because Byatt can adopt different tones and write in different styles; most excellent are her parodies of certain kinds of literary criticism. Possession also suggests the danger of reading through the lens of something—feminist criticism or Freudian criticism or whatever ism, instead of taking the work for what it is. 
The weakest point, which in my opinion does hurt the book, is the poems. When Nabokov writes about a character in his book who is a great writer, he convincingly demonstrates the writer’s talent, because he is a genius. It’s hard to say the same about Ash’s and LaMotte’s poems by Byatt. They are an integral part of the novel (though it seems that lots of readers skip them for the story), and they are there to create the illusion of realism and a world outside the book, to make the characters appear more authentic, more real. They however produce an opposite effect, or at least to me, because the poems aren’t great, they make Ash and LaMotte less real, who are meant to be among the most acclaimed poets of Victorian times, and that consequently makes it difficult to take the academics in the book seriously. 
When I ignore the poems and choose to suspend my disbelief, the story of Ash and LaMotte is moving. But the characters I think more about are Ellen (Ash’s wife) and Blanche Glover. They are not even there, their voices aren’t heard, their thoughts aren’t known, but their implied suffering and baffling actions make me curious and concerned about them, make me want to know them and their thoughts and their motivations. That gives them a vivid existence.  
Another weakness of Possession is the ending. It makes everything fall apart. We have a beautiful and moving story, about love and loss and buried secrets, about things that only last briefly, about a couple that might have been, about a letter undelivered and unread, about a child that is never known… It is beautiful whilst it is tragic, or beautiful because it is tragic. I don’t mind the chapters that take us back to the 19th century and tell us about Ash and LaMotte through the 3rd person narrator, and thus let us know things about the 2 poets that the modern characters don’t know, which works effectively and is incorporated well in a novel that already mixes various genres and different styles of writing. But I hate the ending. It is a cheap device, a silly solution, as though Byatt tries to comfort the audience and wants to pander to them. 
The book would be so much better without that cheap ending.