the idea is that i want to share documents over git
i thought about using Text Document (looks like docx,odt in functionality ) that can be edited with any text editor (
LaTeX is perfect for combining it for git. But if you cannot afford yourself the time to "translate" all to LaTeX, I think a great option that fits your needs is using LibreOffice and saving files in .fodt format (Open Document Text - Flat XML). These files are uncompressed XML, so you can use all the power of git as you can see addition and changes to the document line per line.
This will make merging an easy task. Even binaries (e.g. when you include an image) will be embedded in the document and shown as text. Of course you cannot manipulate them from there but you can remove the whole tag or edit attributes with the simplest text editor.