Cross linked: https://discourse.joplinapp.org/t/question-extendable-ui-plans
Yes, that would be cool. Otherwise each plugin probably will implement this functionality on their own with duplicated code.
A feature I also would like to use is doing multiple searches without overwriting the previous search.
This might be realized by creating a tab, which also has its own search window and note list.
(Note that Joplin can only be opened once)