Agreed, all wallets should included and added to a trust tier chart. Note that multicoin is not the only unreasonable exclusion. Non-reproducible wallets are also excluded, so the monero.com and Monerujo wallets are also excluded. Unless you have a completely controlled and specified environment (i.e. linker and linker version, compiler and compiler version, all needed libraries and library versions, target type), no source code is binary reproducible. You might get it with the JVM or Qt or Go but those are minority platforms for wallets. What counts is that you can compile the code yourself if you distrust the source. Similarly, multicoin is only a problem if monero is "just another coin" and not the primary coin of the wallet or if the code is mixed together so a bug in another coin could compromise the security of Monero. So Monerujo, Cake, and Monero.com should at least be added, even if they classify them as tier two wallets. Stack wallet would then go in tier three since it is multicoin without a Monero focus, and all the other wallets except Exodus for be tier four, and Exodus being closed source would be tier five.

maybe, there are some problems with privacy, when you have, for example, ETH and XMR blockchains supported on one wallet. XMR is save, but ETH shows some halls