Yes, you’re right 
Should’ve said ‘expanded which databases are searched’.
Not anymore (source):
The Podcast Index now lists over 2m podcasts. It doesn’t automatically pull new shows from Apple Podcasts, but even so, has now overtaken the number of shows there.
It’s not known yet. It would certainly be great, and the Podcast Index that AntennaPod can now search through has some features that in the AntennaPod app are not available yet. Apart from country, I think it would be great to filter on language of the podcast.
However, whether a more advanced search gets implemented depends on whether someone with the necessary skills is willing to implement it