I think you misunderstood what jgarzik is saying. The idea is that we store the data in a second blockchain, and put hashes of that timestamped data in Bitcoin, which hashes would also be less than 40 bytes. The reason we did not do something like that is not a matter of "intellectual laziness", but rather of implementation complexity. Counterparty is not a project in computer science; it is designed to be a simple as possible, for the benefits in development speed. Even if we have to store our data in multi-sig outputs rather than the too-small OP_RETURN outputs. Worse is definitely better in this space.
In any case, we appreciate the suggestion, jgarzik, and if you think we're still missing anything here, specifically w.r.t. the space of technical possibilities, please let us know. Thanks.
Also, with the second blockchain, you have a second blockchain to secure, and due to this, Counterparty could not fully leverage the unparalleled PoW security that Bitcoin offers end-to-end. Moreover, unless I am overlooking something here, we would still need to parse out the data from the blocks in that second blockchain (assuming it's a Bitcoin or Bitcoin derivative implementation, at least) to get our stored data. So:
* it would not enable SPV-type Counterparty clients for what Counterparty offers over Colored Coin functionality (i.e. DEx, Betting, asset callbacks, dividends, CFDs, etc)
* it would lessen security of Counterparty transactions
* it would greatly increase the complexity of the implementation (i.e. increasing the chance of bugs and vulnerabilities)
The only dubious benefit would be the *slight* lessening our storage requirements on the block chain (i.e. maybe 20-40 bytes less per transaction?). I just don't see how this would make any sense here.
One more point: Counterparty can bring immense benefits to Bitcoin, and this will especially become more apparent if/as Ethereum (and other similar non-Bitcoin-meta "2.0" type coins) enter the picture. My personal feeling here at least is that Bitcoin may very well need offerings in the ecosystem with this kind of functionality to effectively compete with Ethereum and (future) crowd's feature list and draws -- or risk becoming obsoleted, at least among investors and financial market operators, which offer the ability to bring billions and even trillions into the Bitcoin ecosystem as it gains more recognition, trust, and mindshare with them. This process is, of course, only beginning, but we feel that the clear benefits that the blockchain can offer to finance (for not only Bitcoin payment operations, but for the more advanced finance operations that the technology can enable) will set off the next great phase of Bitcoin's growth, IF allowed to unfold organically.