Hello,
3. Is there a (planned ?) feature to add users own styles ? I mean a WYSIWYM-way, so i could add a style MyNewstyle1 and than mark the paragraph as <p style=MyNewstyle1> and write a css file(s) with this style description later
Could you explain why you want this feature ?
I don't see the need for this feature, but I'm not sure to understand.
If you want to add specific classes, you can do it like Jean-François said, then define their visual aspect by adding related styles in your stylesheets.
I don't see the advantage to let end-users add their styles, since the approach of WYMeditor is to allow the technical user/administrators to define strict boundaries. It's up to the web designers/developers to define classes for each project. They can also have their set of classes to use in all projects, to allow more flexibility than what is available by default.
4. It would be great to see the styles names near thouse little tag marks at the top of the paragraphs, like <p>, applied styles: important, date
Yes, it would be a good feature. In fact you can make it if you want: the actual tag marks are simply CSS background images. You can create a specific background image for each class. You will have some work for each new class you add so it's not practical and it won't work with multiple classes.
There are other approaches like using CSS generated content, but it's not supported by IE, or by generating these labels using javascript, but it's more difficult to implement. It's something we may implement in the next major version of WYMeditor. If someone wants to contribute and implement the feature into the current version, we will be happy to help and assist.