After discussion with @giacomozucco it was decided to depreciate OP_RETURN commitments for contract deployments. OP_RETURN is a legacy scheme required only for the compatibility with hardware wallets (see #62 for some discussion on the topic relating proofs). So while it is important for the proofs to be compatible with hardware wallets, it is not the case for the contracts, which may be rather deployed with HSMs.
After discussion with @giacomozucco it was decided to depreciate OP_RETURN commitments for contract deployments. OP_RETURN is a legacy scheme required only for the compatibility with hardware wallets (see #62 for some discussion on the topic relating proofs). So while it is important for the proofs to be compatible with hardware wallets, it is not the case for the contracts, which may be rather deployed with HSMs.