From a soon to be proper dCS family member so I’m a bit in the dark here 
I’ve read a few postings where users complain about the lack of a scroll bar for navigating through long lists of artists or albums. This is when navigating their library from a local NAS/Dnla server. Now I admit I’m a bit in the dark because I’m still waiting for my Bartok to arrive but can’t you simply tell the dnla server to present the library in alphabetised headings? I mean, with my current ‘other brand’ product, I tell my dnla server to show ‘Album Artist’ and when I select that on my player, I then see each alphabet letter as a node. I can then select a letter and then I see all the artist under that letter. I can then select the artist and see their albums.
So I don’t have to scroll all the way down a list of hundreds and hundreds of artists. I just select the letter, e.g. ‘D’, and then I see all the artists that start with ‘D’. Is this not possible with Mosaic?