What if the core devs shorten the OP_RETURN again?
Eligius has set the OP_RETURN limit to 80. Not sure about the other mines.
Besides, I remember that the devs said that even with 40 bytes OP_RETURN (possible for a simple Counterparty asset send, for instance) the transaction takes too much time to be confirmed.
I guess that consensus takes time to achieve. Medici could help them change their mind.
OP_RETURN in Counterparty is currently not used in lieu of multisig transactions due to, as a comment in the code states, BTC Guild doesn't mine OP_RETURN. Hopefully sanity will prevail and 80+ byte OP_RETURN will be widely mined.