May I know is there plan on when will proper structured search be implemented? Document (http://www.texmacs.org/tmdoc/main/editing/man-search-and-replace.en.html) says "In the future, we plan to implement a more powerful search and replace mechanism for structured text. "
As far as I know only Joris van der Hoeven can answer your question (I do not know if @darcy and @mgubi agree with this statement).
Since he does not read the forum, you might perhaps reach him by posting your question on the mailing list.
Yes, for these structural improvement & long term plans it is better to ask in texmacs-users or texmacs-dev.
It does seem this document is seriously outdated. There is some structured search and replace in place. What is it you are trying to accomplish? Might be worth checking the builtin manual or the Jolly Writer.
I plan to work a bit on putting on the web the online manual with a “modern” styling. We need to take more seriously the web presence.
The current searching is primordial, I think, and some version of GPT might be much better at this.