Trading between players is awful idea, it gets suggested every few months, and it will never work unless they put some big ingot tax on it so f2p can't use it at all, otherwise everyone will just use alts, if people bother to make alt for plundering they will definitly make some for trading.

As for tradings fragments for other ninjas, that already exists, you can trade fragments for Iruka or Chakra Naruto. Actually wouldn't be to bad if they added more redeem options there for different ninjas, but oasis won't do it, people crying to make sage based on power from first month of game and they can't even do that yet