Yes, diversity is good. If you do decide to go for it, do lots of testing on either the test network or with a testnet-in-a-box setup before even THINKING about handling real bitcoins. If you screw up and lose other people's money it will take a long time to earn back their trust.
What are peoples' thoughts on creating a compliance test suite for Bitcoin separate from the existing C++ client, and ensuring that both the existing C++ client and new clients (e.g. bitcoinj, bitcoinp) pass the suite?