A large reason why many of the maps you mention seem to be dead is because they are quite boring by design. Most people don't want to spend time on maps like South Pole or Last Cave because there isn't much to them. These fairly vacant maps leave very little room for imagination. Maps like Fluorite and Bonfire, on the other hand, have at least a bit more trees and dens and seem fairly more "lush" and lively. I think it's also human social nature to want to gather where there are larger groups and naturally abandon the more isolated maps.
Another thing to take into consideration is that most users here are young. Some are attending high school or elementary still and have little time to devote to Feral Heart in between studying, class, and homework. Some users are also working or attending college. This month is dreaded exam week for most college goers. I for one haven't been online to often due to the immense work load with papers and finals as well as registration business for next semester etc. Elementary and high school users also should be preparing for their own finals and last classes soon. If most people take their studies seriously I doubt you'll be seeing to many people on these next few weeks.
I disagree with the whole FH is dying thing also. This community is far from dying. What it has are highs and lows when it comes to activity. Some months are more busy then others as are some seasons like summer when most are out of school etc. Weekends around here are still a maniac fest... lol If you want to see lively come online weekends at early hours.
When it comes to lack of interesting rps I think that perhaps you're not looking hard enough. I got myself into some rping adventures the past month or two and have found myself in pleasant company in quite a few interesting rps. Sometimes all it takes is for you to put the spark out there and you never know what you can start. If you've got ideas of interesting rps bring them out there. Some users do lack imagination sometimes but with the refreshing inspiration of new ideas from another come great things. Some users are also afraid to try new things because of either lack of proper knowledge or fear that others won't be interested or will tease them over it. Although some rp themes are a bit over used most are popular and under stable to all so that's why you might see a lot more common themes around and less specialized ones. You also shouldn't under estimate the potential of over used themes. There is always a new way to refresh an old thing.
Lastly while FH hasn't been updated in a long while that isn't much reason to see it as dead or boring. The whole concept of creativity is the life blood of this community. If one losses their own creativity that's when the world of FH starts to dull to them. If you continue to see the game as the empty canvas that it is you'll find it much harder to tire of.
To me every time new users join, the game updates itself because with them come new personalities, new ideas, and new adventures.