Update Suggestions for v9.25

Just downloaded v2.94 and whilst using it, I've realised that it hasn't had any major feature upgrades or a facelift in a long time so I'd like to make some suggestions just to help out. First, I'd like to suggest a facelift similar to Audacity. Give the outlines a softer look and maybe slightly give the edges and corners a curve. Maybe even fill the boxes with different shades for different situations like Red for empty space, yellow for errors, and green for success. Even adding a different font would be a huge change. My second suggestion is to change the logo because, in my opinion, it looks very outdated and unofficial. I bet it was really good around 2010 but now it could be something newer. I'll add a preview for a new logo exemplar along with this text. My third suggestion is to maybe add a library application or program for both PC, Mobile, and Console. This application could store movies and music in one place on the cloud that way no matter where we are, it is always at access in our library, maybe with under 16GB free storage making it better than Google Drive, and Microsoft OneDrive yet still with a reasonable amount. We can even add a personalisation, equaliser, community profile, and video effect settings menu. I'd find this very useful, especially if we could still change the information of the file as our current mp3tag does during use. If this were possible, I'd definitely be using this over Samsung Music right now. Maybe even add a subscription option of storing over 16GB on the cloud to make you money and keep the website up and running. I'd definitely be paying $10 a month for this to happen. My final suggestion is to add the option to import a picture for the artist. Most applications for music these days like Google Play Music, Samsung Music, and Spotify have profile pictures of the artist. The one thing that bugs me is seeing an incomplete artist profile whilst listening to Eminem, Korn, or Linkin Park. This suggestion is the most demanding of the four by far as it will improve the completion of my projects completely. Thank you for reading my long and very detailed essay. Hope to see some great changes in future.

Where would you see such states?
An empty tag field is no error but simply not there.
What could be an error? Not filled? See above. Filled? User input is taken seriously and does not get evaluated.
Success? You get a message box if you want. As described before, fields would most likely be always in a success state, so the added colour would not add any information.

So far, MP3tag is a tagging program, no collections maintenance or managing program. The currently library is only used to improve performance for large collections.

It is already possible to add a picture with the label Artist. The problem is: hardly any player can deal with it.

There are numerous posts that complain about performance even on a NAS. A NAS is usually situated in a local network and has definitely a faster access than accessing files in a world wide network but also definitely slower than for files on an internal HDD or SSD.
Tagging, as you suggest, a movie file with gigabytes to first be transferred to the computing device and then back again will make it a patience straining affair. I doubt that this will ever be a frequently applied use case.
I would still copy files once to my local device and then, after the tagging is done for all the files, re-sychronize them with that remote storage (if I use such a thing at all).

I think that this does not always work. At least WMP blocks files so that they cannot be edited while being played. So it depends a lot on the environment and is mostly nothing that can be done on MP3tag's side.
I am not quite sure whether you suggest that editing tags on a mobile phone should be possible. Looking at the fairly wide file list that I use I doubt that this display would really be suitable for a mobile phone. Losing half the screen for the screen keyboard would reduce the space for the display of file information even more. Even though it might be technically possible, I still doubt that it is a valid use case.

By success, I meant like a valid input. Something to say all inserted characters and letters are accepted in the text field. For the yellow, think of how the file explorer in Windows 10 states how some characters are not accepted in a file name. Something to identify that issue that way we can just continue with the next box until it is time to come back to that issue and fix it. Just to speed things up. One task at a time. I've been studying all sorts of different imagery code and soon I'll be beginning to customise a different operating system with the basis of Windows 10 for myself. That should explain why I'm a bit picky with this suggestion which I'm sorry if that did make it sound like an insult. This may seem like a waste of time and resources, but I was always about making things more attractive. It may not seem as much as a big enough deal for you but for people like me who want to tweak with it and see what it can do, it's a bit hard to see what some icons and actions do. If you really don't think this is a good idea or useful in any way, you don't have to reply as I completely understand. I do realise it's just for function after all.

I still wonder what kind of characters you think of when you say "valid". AFAIK there are no invalid characters in the text fields.
Either you can enter them, then they are valid, or you can't - then they are not there.
There is a function to validate text if you intend to modify the filename with an action or a converter.
But I have never seen states in MP3tag, like you describe them, during editing.

Whenever I add brackets, slashes, or a column to the title or artist name in MP3Tag, Samsung Music, Google Play Music, and iTunes is unable to display the name completely because the characters in the name was not supported. I never knew the title of the song until I played each song one by one and renamed it. As you can imagine, it took quite some time with 1000 of my songs affected. I just thought it might have been possible to display that issue to try and prevent others from having this issue in the future.

Where do you add these characters?
In one of the fields like TITLE or ALBUM or are we talking about the filename?

Windows 10 may not have as many expectations despite still having just a few, but it's certainly an issue with mobile devices. Title and album specifically. The file name doesn't affect it. I'll try to add a song like 'Stan (ft. Dido)" and the title doesn't appear. It was first discovered on my HTC Desire S running Android 3.0

But this is a problem of the target player, I assume.
How should MP3tag be able to guess what glitches other programmers have built into their programs?
ID3 UTF-16 allows the full blown 65536 characters.

BTW would lead to a perfectly valid filename, so not even explorer would show any kind of alert.

My new 2018 Samsung Galaxy J2 Pro runs Android 7.0 but it only accepts these characters either as the default name which I obviously want to change since I download through a YouTube converter and the title is messy, or if it is an mp4 file.

You can either use a filter or add a column that tells you if there are characters in a field that might lead to problems.
But as these characters seem to vary from target system to target system, you probably have to create several columns.
And then you have to think about a way how to keep the original information and feed the buggy players with their customized information.

A definable color for a tag without a data in it is something I am longing for for a long time now. And in a more advanced version, a different color for a tag field with certain definable data, like for example white spaces. The user could add as many colors and rules as in need of

With such functionality I could spot certain errors, specially when I am tagging new files from a scratch and have to have in mind a whole bunch of rules that I follow [in hope of keeping a unified system]

I do not concur. But if new icons are implemented, I would like to see an option for using the old ones

I remember the case of an excellent burning software called Nero. At some point they added so many over the top functions that I simply stopped using that garbage, which it simply became at that point

I never thought of that. But one picture for one artist could be something nice

But how to do that? Assign a picture to a folder. To a keyword in a given field [e.g. "Michael Jackson" in "Artist"]. How about if there is also a featured artist- should we see two pictures at the same time?

It is official then: I am a weirdo, because I listen to the music with my ears and not eyes