That is not our only problem with the json interface. Namely, the info() method doesn't work at all due to a slight coding error in patching together the query string.
I made the necessary changes and put them in testing already: e3d5bd40a32b2421197b392add824d328c99d817 cccd21922904d4d56230301bdf9de4e98d9673f9
I also changed the search method to behave the same way the AUR's web interface does, although I think the fulltext search may be superior, it can't search for parts of words which may be a drawback depending on who you ask.
Removing fulltext searching makes it super fail now. Not sure why/how you think these changes make it better. Not sure if pulling in modules on the fly is really a good idea either. It may be better to test for the module, and not provide the aur_json interface if it doesn't exist. As to the query string being wrong..That regression crept in as a result of the request for info by package name as well as info by package id. It would have been nice to have people actually testing it.. *sigh*