The BTC transaction fee periodically exceeds $0.01 per byte. Therefore, shaving off some bytes really adds value.

Here are some ideas:

The CNTRPRTY prefix applies to every Counterparty transaction. This can be reduced.

Allow Asset Name as alternative to Recipient Address . The asset name is alias for asset owner address. This reduces the byte toll from 21 to 8. Some very positive side effects are human readable addresses (send to JOE.DOE) and flexibility in changing underlying address by transferring ownership.

Multisend formats use 6 bytes for Asset Qty (down from regular 8). Max token quantity in one send will be 2,814,750 which is ~$28,000 worth for penny-currencies like PEPECASH and FLDC, and $30,000,000 worth of XCP. If someone needs to send more, the wallet software must either break into several sends within same multisend or require an ordinary enhanced send.

Give XCP index 0 by default in asset tables for multi-sends, thus eliminating the need to define it in every single send.

Use a compression format on counterparty data.

It makes sense to look at the relative saving of each proposal on each send type. A two byte saving on a 250 byte enhanced send is a meager 1% saving. A two byte saving per line on a multisend, assuming each line is 35 bytes, is a much more significant 5.7% saving.