One quick thought on increasing viewers favouriting-it would be nice to have some carrot to make people favourite more, one common software carrot is a 'suggested synths' being a part of a 'your favourites' section (I'm thinking of the World Music picture from seadragon while I write this listening to LastFM :). At the moment favouriting synths doesn't appear to have much to it other than to pimp the rating of synths in the 'top favourites' section, and, if people click a name they can view others.
To make more people favourite I would look into two more options to the Explore page below Map Explore
Your Favourites (view on map would also be nice ;)
Suggested Synths (link by similar geotag/country, link by common favourites with other users; by tag; 'follow user' to get updates on new synths by an artist; list users who like it; and on and on)
This would definitely drag favourites to the front rather than having it as a bit of a bolt on?