Lets invent a good altcoin with a real chance to take off and maybe even replace Bitcoin.

We will design a new scripting engine, mostly backwards compatible with existing Bitcoin scripts, but it will have some bugs fixed and new features: “strip” opcodes and checks on canonical encoding of data and signatures to prevent malleability, references to past and future transactions (so we can lock up outputs for a specific future transaction), improved SIGHASH_* flags and some additional ones, enabled more complex arithmetic and boolean opcodes, isStandard checks replaced by a dynamic mining fee requirement proportional to complexity of opcodes and memory used (inspired by Ethereum), Ed25519 signatures, blind signatures/accumulators like in Zerocoin and even Lamport signatures to allow swift transition to post-quantum crypto if needed.

This scripting engine should be implemented for all major Bitcoin implementation platforms: C++, C, Ruby, Python, Node.js, Objective-C and Go.

This altcoin will use standard Bitcoin scripts by default and only use the new scripting engine via a versioned P2SH-like output script compatible with Bitcoin:

OP_HASH {hash of the altcoin script} OP_EQUALVERIFY {version}

{version} will be OP_1, OP_2 etc till OP_16. Version 17 will be “OP_1 OP_1”, version 18 — “OP_1 OP_2” and so on. Version will be increased when scripting engine is updated with new features or incompatible improvements.

This altcoin will inherit existing Bitcoin wealth distribution. All existing wallets will be compatible with this altcoin from day one. Only miners will need to perform a “soft fork”, by agreeing to enforce new P2SH scripts using new scripting engine (like they did in early 2012 with BIP16). Once super-majority of existing miners enforces specific interpretation of such scripts, it will be safe for users to create transactions using the new scripting engine. Legacy wallets will acknowledge and validate such scripts, even if they won’t be able to create new scripts and contracts themselves.

Unlike many other altcoins, this one will have better chances acquiring big market and hashing power, and thus would be potentially more useful than other altcoins designed to enrich founders at the expense of naïve enthusiasts who do not understand economics and money.