Receiving all unconfirmed txn without witnesses is 1.6kbyte/s or less.

Sitting logged into many websites more bandwidth than that.

The proposed protocol seems like it uses a pretty significant fraction of the bandwidth as sending the transaction. It also requires hashing the transactions in the mempool to do the 'short id matching'.

The BIP text is also underspecified in that that BIP152 hashing scheme is salted with the block hash, and there is no block hash for unconfirmed transactions. Without an attacker unpredictable salt BIP152's short hashes are particularly vulnerable to collision.

Unconfirmed transactions are generally a major vulnerability in lite wallets:  A number of years ago there were a bunch of nodes on the network that generated fake 21 million btc payments to every recently used address and handed them to lite wallets that connected to them, causing them to display enormous fake unconfirmed transations-- and for some software like android wallet, it made them almost completely unable to make payments until you restored the wallet from a backup. Not to mention the hiding issue.

Is there really a particular reason to filter unconfirmed transactions at the expense of privacy--since what txn you fetch is still visible?  With BIP 157 when a block matches the user fetches the entire block, at least somewhat preserving the anonymity set.

Aside, the graph should show getblocktxn not blocktxn.  I believe the 'getcfproof' message could also work by index instead of txid like getblocktxn does, for a massive bandwidth reduction.

I doubt there will be much appetite for any commitment structure that requires recomputing the commitment any time the txn list in the block is changed. Particularly any that involves doing it for 5 different kinds of filters and which will go out of date as scriptpubkey types change.  The BIP157 design being completely agnostic to the content of the scriptpubkey was an intentional design to conserve storage and optimize for the possibility of eventually turning it into a viable commitment.