40 bytes is more than sufficient for all legitimate needs for tying data to a transaction
To me the word "legitimate" is the main problem.
Who can claim the power to say: this data is legitimate and that another is not legitimate. This is called censorship!
The question can not be: What data is legitimate to be stored in the blockchain?
Because this is a subjective question, and that no one can claim to have the answer.
The only question is: Should we allow the storage of data in the blockchain?
And the answer is: there is no choice, because it is possible to do with multisig transaction.
So the question becomes: Should we let people store data in multisig transactions or provide a cleaner way to do it?
History has shown that it is much smarter to regulate than to ban something that is impossible to ban.
If OP_RETURN can go from 80 to 40, then it can very well go from 40 to 32 bytes if it catches their fancy. I understand why the word cabal was used in conjunction with the bitcoin core dev.
Since that particular decision is arbitrarily in the hands of people not associated with 2.0 projects I would argue that it should not be relied on even if it is possible. Our current solution works a 100% and will continue to work in future. Using OP_RETURN puts us at the mercy of people who seem to have a very rigid outlook of the future. The supposed free rides are the projects that will enrich bitcoin and make it competitive against the next generation of cryptocurrecies. Relying on the Bitcoin ecosystem to carry the day is incredibly shortsighted.
A reliable hackish solution trumps an unreliable elegant solution any day of the week and twice on Sunday.