I'm trying to migrate from MS Word to Latex. Collaboration features are a tricky part. In essence, I'm looking for a LaTeX or similar language editor which supports

• work on complex things like 2 columns and subfigures
• tracking changes - automatically underline when i add text, strike out when i delete
• preferably wyswyg
• should be possible to merge changes from version 2 and version 3 into version 4
• each change should be accompanied by data as to who did it
• such data should persist across all future versions
• easy export to formats that make sense

I've already found

• LyX, but its track changes feature doesn't include author information
• TrackChanges style and GUI component.
  • The program itself only has a style which adds \add[Autorname]{new text} and \remove, but collaborators are supposed to type them into the latex file by hand.
  • The GUI component allows to accept and reject changes. This is good. :-)
  • The changes are added into the file (apart from in a not-wyswyg mode explained earlier) not interactively (I can't just select a block of text in latex source and start typing new text and expect that it adds the relevant \remove and \add blocks automatically).
• GNU TexMacs, it has a versioning tool. It does involve saving old and new copy of file by hand; each tracked change does not include its author, which it should. (GUI for making these changes and for reviewing them is present.) "Subversion support" is mentioned but not documented.
• The option of using git with LaTex files. Provides a good overview but only in terms of raw markup. It should be nice to have a graphically represented view of changes, notes, and the like.

I've already read these questions

• "Track changes" in LaTeX - highlights latexdiff, changes package, usage of plaintext latex and a version control system; suggests using TrackChanges, but it is not fully WYSWYG; suggests using pdf
• Keep track of changes in LaTeX document discusses change{} macro regardless of software
• What is a good way to show changes between two versions - latexdiff and texdiff, involves people editing a latex file directly and saving the new file + the diff. harder for leaving notes and more than 2 people though, i.e. should be possible to view multiple changes in 1 file with author for each change; changebar is also suggested but it's again manual edits of the raw latex markup
• Mark changes since last edition with bars in the margin more of the same, but margin specific
• Environment to underline/strikeout for comparing versions more of the same; author of each strikeout or change is not saved for a next collaborating person to work on it