I finally came around to finish the Blockchaincom wallet write-up.
The Blockchaincom wallets follow the feerate recommendations of the Blockchaincom API closely (or over/underpay by a fixed percentage due to bugs in the wallets). This allows to identify a majority of the Blockchaincom transactions by combining the fingerprint and the feerate recommendation. I still believe the reported network share of one-third of all transactions is reasonably accurate.
The full article is here:
Following the Blockchain.com feerate recommendations -
Wallet fingerprinting nearly a third of all Bitcoin transactions -
https://b10c.me/mempool-observations/3-blockchaincom-recommendations/Feedback, ideas, and potential future topics to add to my already long list are welcome. However, I'll be busy with other things in the coming weeks.
As said in your article the ability to deduct the wallet used for a specific transaction is a data leak. However I also think that if a third of the transactions is using the same Blockchain.com feerate API also centralization is an issue. As user of this wallet you have to trust the estimated fee to be correct. If Blokchain.com or a third party would manipulate the outcome of this API than almost a third of all on-chain transactions could be tampered with.