I am excited by the discussion here. I would love to see some usage of AJAX/jQuery in future versions of phpBB, especially in the ACP and MCP, as many people have already pointed out. I also agree with
idiotnesia's post with regard to changing the reordering of forums in the ACP to use a drag-and-drop type of functionality. Of course, I'm not very versed in AJAX or jQuery, but I do know that it would be nice to see some implementation of it in Rhea, no matter how small (or large) it may be. I like the idea of an "undo" option instead of using these constant confirmation pages, but the developers have better insight into what it would require to do that sort of thing.
Also, even though this can be accomplished without the usage of AJAX/jQuery, I think it would be nice to allow members to login using a login box in the header bar of the forum without having to click the "Login" link, and once they login, it will take them right back to the page they were previously viewing without showing any type of login confirmation page. I've always disliked how, upon logging into the forum, it would always redirect you to the board index instead of the page you were previously viewing before logging in.
Well, there is my 2 cents. In any case, I trust that the dev team knows exactly what they're doing with regard to including such functionalities in future versions, and I doubt they would go overboard with it like some people are worried will happen.
