At this point the PdfFormatProvider does not support floating images and these elements are skipped when exporting to PDF.

The feature is trivial for floating images with "Behind Text"/"In Front of Text" settings, but otherwise floating images are affecting the text layout in complex ways.

Add support for shapes, and especially for shapes with textual content. 
In OOXML, shapes are represented by the wps:wsp element, and shapes with textual content by <wps:txbx>, <w:txbxContent>.
Such shape can be added to a Word document using the Insert -> Text -> Text Box -> Draw Text Box, or through a shape's context menu -> Add Text.

Do not confuse these shapes with Text/Rich Text content controls (see https://feedback.telerik.com/Project/184/Feedback/Details/190057 )

At this point, the justify alignment is not supported. Provide the ability to export text with this setting.
This functionality is dependent on PdfProcessing: Provide API for setting the text alignment to Justify

Implement nested mail merge and master-detail scenario.

This feature includes: table of figure, table of tables etc.

TOC field contains PageRef fields inside it. To update it, we will need pagination (layout) support and PageRef fields implementation. Also TOC update can be influenced by TC fields presence in the document.

Implement export to PDF.

Implement support for content controls (a.k.a. Structured document tags), which will allow inserting editing controls in the document:

- Rich Text
- Plain Text
- Check Box
- Combo Box
- Drop-down list
- Date picker

Do not confuse this feature with form fields support (see https://feedback.telerik.com/Project/184/Feedback/Details/219850 ).

Implement repeating header row for tables when exporting with PdfFormatProvider.

A similar functionality can be achieved using the editing API of RadPdfProcessing. There is attached a project showing a sample implementation. More details are available in the forum post at http://www.telerik.com/forums/repeat-table-heading-after-page-break#kH616fyAKUiDl6WAknUILg

The API should allow you to perform a text-based search and return the parent element(s) of the result(s) or directly the found element(s).

The attached sample project below demonstrates a possible workaround for PAGE and NUMPAGES fields when exporting to PDF. The demo shows how to generate document from scratch containing PAGE and NUMPAGES fields and export it to PDF.

These file formats are very similar to DOCX, and can be easily imported with loss of some information (e.g. macros).

Implement import of PDF to RadFlowDocument, using PdfFormatProvider. This would require text recognition (including determining where paragraphs end as opposed to new line inserted because of the layout) and table recognition.

This will allow conversion of PDF documents to docx, RTF and HTML.

Enable the customers to work with .doc files.

In WordsProcessing you could set 

table.Alignment = Telerik.Windows.Documents.Flow.Model.Styles.Alignment.Center;

But when the document is exported to PDF, this is not respected.

Introduce an option to replace a Run text with line breaks and/or new lines or with other document elements such as Table, Image, Paragraph and etc. 

The following code snippet shows how a Run can be replaced with another inline element:

RadFlowDocument document = new RadFlowDocument();
RadFlowDocumentEditor editor = new RadFlowDocumentEditor(document);
 
editor.InsertText("text");
editor.InsertText("REMOVE");
editor.InsertText("text");
 
foreach (Run run in document.EnumerateChildrenOfType<Run>().ToList())
{
    if (run.Text == "REMOVE")
    {
        Paragraph paragraph = run.Paragraph;
        int childIndex = paragraph.Inlines.IndexOf(run);
 
        ImageInline image = new ImageInline(document);
        using (Stream stream = File.OpenRead("example_image.png"))
        {
            image.Image.ImageSource = new Telerik.Windows.Documents.Media.ImageSource(stream, "png");
        }
 
        paragraph.Inlines.Insert(childIndex, image);
        paragraph.Inlines.Remove(run);
    }
}

Respect the Height property of TableRow when exporting with PdfFormatProvider.

Both properties table cell padding and table cell spacing are not exported to PDF format.

Form fields are the legacy way to insert an editable controls in a document (text boxes, checkboxes, dropdowns) by using the FORMTEXT, FORMCHECKBOX and FORMDROPDOWN fields.

Do not confuse with content controls (structured document tags) (see https://feedback.telerik.com/Project/184/Feedback/Details/190057 ) and with ActiveX controls.

Introduce new section properties which are responsible for defining columns in the section.

Take into account the table row's CanSplit property when exporting to PDF from RadFlowDocument model. Is set to false, the table row should not be split between two pages, if possible.

This property could be set to false, for example, when importing MS Word documents with "Allow row to break across pages" unchecked for some table rows.

The custom document properties enable the users to define their own properties to the document or use one of the predefined. 

In most of the cases, the document variables can be used instead. More information about them you can find at http://docs.telerik.com/devtools/document-processing/libraries/radwordsprocessing/concepts/fields/document-variables