Just put up a poll about zerocoin implementation at the top of this thread. We want to know what you guys think
I don't think I can vote in the pool (new user account, perhaps?) but for what it's worth, my two cents would be to suggest implementing Zero
cash's anonymity system, which could also be done by hardfork.
Zerocash's JoinSplit framework is substantially more usable in practice than the Zerocoin mint/spend system (no fixed denominations required, smaller proof size, faster verification), and Wyvern would benefit from / could integrate with further developments and infrastructure made for the Zcash system, which seems far more likely to gain adoption than Zcoin's.
(implementation may be substantially more difficult, however)
That said, in preference to both of those options, I suggest a third.
From what I've seen, the private transaction implementations in both Zcash and Zerocoin are years away from usability for even a reasonably knowledgeable consumer. Both have presently unsolved scaling issues - Zcash on the proving side, Zcoin on the verification/storage side, both require the user to understand several distinctly nuanced concepts (shielded/unshielded address, mint/pour) quite accurately in order to actually protect their privacy while using the technology, and neither has (to my knowledge) an accessible third-party wallet implementation (e.g. Jaxx) that employs the privacy technology implemented by the coin (Jaxx, for example, supports Zcash but only using unshielded transactions, which completely negates the point of the coin).
Rather, I suggest Wyvern implement Segregated Witness. Segregated witness - while perhaps not a great solution to the blocksize problem facing Bitcoin - is an excellent solution to the transaction malleability problem, is quite well-vetted technologically thanks to the blocksize debate, and is probably easier / less risky to fork into the coin than either privacy implementation. Segregated witness would allow for a Wyvern lightning network, which has numerous thematically suitable usecases. Such a Wyvern lightning network, for example, could be used for in-game transaction settlement (allowing Wyvern to be used as a cross-game virtual currency), in-game microtransactions, or just faster confirmation of game purchases on the Wyvern Exchange (since transaction malleability is no longer possible, accepting and chaining unconfirmed transactions is possible). Implementing Segregated Witness would also distinguish Wyvern as the only ASIC-resistant cryptocurrency with a lightning network (the others being Litecoin and potentially Bitcoin).
A privacy implementation can then be forked in at a later date - when the technology behind Zcash/Zerocoin has had more time to iron out its usability/scalability issues.