I live in Texas and ping 50 to Japan, so I don't quite understand high ping....
Drachenfels is in Germany, Poland should ping <80 (with pretty garbage internet, 10-25 megabits per sec) which makes it very possible to do high end pvm and pvp. I know of someone who plays from Brazil to a US server and has 150-200+ ping always, still does high end pvm(solo I might add). Though I do believe the addition of a South American shard would be beneficial for the players in South/Central America, I do not believe that it would be a great idea to add another shard to the game or move one. It is not so simple to just move a shard from one place to another, they'd have to own a location where they could run the server from, have maintenance workers paid hourly for said server room, rent, utilities, security, etc. Financially speaking, it would cost more to move and run the server than it would be to keep it where it is and lose a few people that don't wanna play due to ping.
Oh, and we do pvp on our small shards, just not to the capacity of Atlantic or other low/medium borderline pop shards.