Hi Moroz, Ralf from WOS here. We already know each other 
People here are unfortunately not very active, they read but don't write, so don't worry if low response happens 
Hello Ralf!
It's not a problem - to get high response we should make something really outstanding

It would be good if people here would just now that there is ZX-Art and it's been updating for the beginning. When we get more outstanding features/content, the response will come

Is it really necessary to do such big amount of work? There are already sites with such content - WOS, Virtual Tr-Dos, Pouet, Demotopia, ZxAAA...
I believe that it is really necessary.
WOS was not updated for some time. It has some promising changes now, but at the moment it's not openly moving anywhere. It still has nice chances though.
Virtual TR-Dos is just too old. No comments, no ratings, no authors, no screenshots. It's even hard to select the game release sometimes. It surely should be updated, but no one is willing to.
Pouet is a demoscene only. No system tools, almost no games. It's also crossplatform, so it's hard to make a good easy focus on ZX Spectrum there.
Demotopia is not updated. Demozoo is great, but it looks like pouet2.0 to me. It's crossplatform and only demoscene-related. For someone it's a plus, for many these are minuses.
ZXAAA is demo only. It's a great archive, it even got RSS feeds on last week, but overall its development is too limited by its owner, who is already happy with what he got.
I think more about great systems like CSDB, but more user-friendly and modern, utilizing the best of modern web technologies.
But I would really like to see a good collection of ZX music, there isn't such thing on the web now.
There is an impressive database of music - zxtunes.com
Unfortunately, it's not updated since 2006. It's author - newart - was planning a new version, even made some prototype like I heard, but never showed it anybody. We had a nasty online fight with him in January, it's not a really beautiful story to tell, and full of drama as usual

However, since the zxtunes.com wasn't updated for 8 years I decided that I should stop supporting only graphics and made functionality for music playing, since I already had most of structure and navigation for graphics, I could easily adapt it for music. Nearly same time I decided that I won't be able to make everything alone and I asked some of well-known sceners for help. Now we work as a team and we try to make a portal which would not depend on a one person's desires and opinion.
Next steps on ZX-Art would be:
1. Content editing by registered visitors. This way everybody would be able to upload/edit/delete his own works at any time.
2. Open API for everybody to use the information freely everywhere.
3. Integration with other ZX-Spectrum related resources. Info from ZX-Art should automatically appear in Demozoo at least.
These steps would guarantee that ZX-Art will become really community-driven. I will even give server access to well-trusted sceners for the case I become mad or accidently die, so the portal with all data would be safely copied, alternative version would be started and gathered legacy would not be lost in vain.
There is a collection on Sergey Bulba site but it's just one huge .zip file. I'd like to see a database of music where:
- you can search by author
- you can see real names of authors if known, not only nicknames
- music is linked to game or demo
- music is described by tags: "techno","ethnic","romantic","joyful" etc.
- if music is a cover of well known song, then the original name is mentioned.
and probably some more features I can't think of now.
We already have search by author.
Most authors already have real names.
Music is not yet linked to demos, but can be linked to game.
We already have visitor-edited tags for music.
There is no possibility to set a original name for covers, but I will add it really soon.
By the way, I've implemented most of your suggestions from WOS. In fact, almost everything can already be edited by registered user, I haven't just yet made an official announcement

Good luck with your project!
Thanks for the kind words!