I don't know of it has been suggested before. It might be buried in some other post. If so, sorry for the repeat. How about being able to trade EP for BP? I don't think it should be 1:1 but probable 3EP for 1BP. I have huge numbers of EP that I don't think I am likely to need. But, BP are like gems, highly needed and hard to accumulate for the upgrades that require them.
How to collect BP up to 1000 or more with fishing is mention in some threads. After upgrading Academy and both Mystic Mortars you need only a few BP for Observatory. With Pirate Catcher and Trainings Camp which both needs EP every 26h, EP is now more valueble. Maybe we will need in future EP for buying new maps to exploring. On the long run I don't see a need for EP to BP exchange anymore. Btw, attack the chinese new year ships as long as they are on the map. Very often you can earn BP.
