Gameforge may not be aware of the original reasons why the ratio of rubies per diamond purchase from item shop was as high as it ended up before the latest changes.
The changes happened because it was impossible to get enough rubies to buy all the required items from the ruby part of the IS. Unfortunately, the changes went too far and we ended up with a glut of rubies on the old servers.
Now, on the new "Steam" servers, with the reduction to 10% rubies to diamonds and the transfer of large numbers of items from the ruby to diamond shop, we have returned to the original problem.
My suggestion is to either increase to 15%, the no of rubies per diamond purchase, or put most of the things you moved to the Ruby shop, back to the diamond shop, or at least make those items available in both.
While the current situation will reduce the glut of rubies on existing accounts, it is a deterrent to new players anda problem for existing players on the new servers (as rubies are server specific).