If you started, just finish it - turn it into a full node.
It will give you a great satisfaction and the community need other clients.
Bittorrent would have never became a success if people would have stuck to the original python download dialogs.

Personally I believe that the future of bitcoin is not in the official client - the official core is just too important and no sane developer will want to risk breaking it, which will surely paralyze its further development. Since it will be harder and harder to add new features there, sooner or later alternative clients will just beat it on the functionality and a speed of development.

As for your further possible concerns, since I've been there I can tell you that the biggest challenge, besides the ECDSA performance, is a proper database for UTXO.
Forget about anything SQL based. Unless you want to make a node for testnet only