[DaveBlake]

For a better music experience, besides custom tags, it would be nice to have the possibility to get to items more straight and direct.
It would be nice to jump directly to the album or artist of currently playing song, to look at the album or other albums from this artist. Maybe even genre or custom tags could be included

Agreed. Bi-driectional navigation e.g. having selected a song link to the album (maybe even albums if you have compilations too and mbids to identify the recording), or artist(s) etc. or from album to artist etc.

When playing a real CD or Vinyl, I'm not only viewing the front cover, but am able to turn the cover to see the track list.

Do you mean having more than one image per album? Or having a songs list in a panel when an album is selected on album node?

Picking up the museum idea, I would surely like to look left and right of the current item found. Maybe head for something I know and get inspired from there...

Up to now I haven't found a quick and intuitive way to get to 'relations' of what I'm currently playing. Examples are:
* show releases of same genre and year
* show albums of same artist
etc

I get the idea, but how would we define "related" items? Surely we need to let the user choose the criteria? But interesting.

Sorting music in "hardware", I never would expect Jazz in the same space as Metal. Genres are nice, but the discussions on genres is well known (could be just 5-10 or 500-1000). So custom tags come in handy here, having some main genres within custom tags like 'Rock' (which sums up Hardrock, Postrock, Metal, Punk for me), Jazz (New Jazz, Experimental, Swing, etc)...

I do think users need to get control of genre, certainly in what they tag. Scraping online genres for artists and albums can resuklt in a mess too - do any of us agree on genre? I want to get Kodi to propagate song genre into artist genre, and allow the user to refuse the scraped values that come with other nice things like biogs. I also wonder about having a genre / sub genre relationship, sort out the Hardrock, Postrock, Soft-rock etc.

What I am saying is that we tackle the genre mess independantly of having a hash-tag or custom tag facility.

My main problem with music in Kodi (and with all tag based players like Ipod fi) is that there's no way of 'own ordering' my music. Databases are a nice to have, like catalogs in museums are, but the art displayed in a museum isn't unordered.

It is the database that makes ordering possible, although Kodi only offering a limited variety at the moment (and has some odd bugs). But what do you mean by "own ordering"?

Widgets are nice, too. But even there I haven't found a way to 'jump' to a random album displayed in a random albums widget, but only am able to play that album. If I like to draw a path from there, I start listening to a random album, I have to be able to get to wherever I'm inspired from by that album in a quick and intuitive manner. It even takes "millions" of buttons to get to the current playlist...

In a museum I'm able to start and go on from there. Head left for photography or right for paintings. Head for the upper floor to see more experimental or contemporary art or downstairs to see Mona Lisa :-)

Agreed. From any item, any where (nodes, widgets etc.) you want to be able to play, but also go to related items and chose that relationship e.g. other items by artist, other songs on that album etc., other items that genre, other items that year, other items that genre and year, other items with same hash-tag or combination of tags.

Keep the ideas comming.