This is exactly what I said. To upload a signed message containing the hash instead of leaving a hash solely.
There shouldn't be anything wrong with this and it's quite faster than the other method.
I might be misunderstanding your question/comment, so I'll try to get a handle on it:
You're suggesting that (like the bitcoin core dev team) the Electrum dev team should post a PGP signed list of checksums, correct? Although there's nothing wrong with that, I fail to see how that's faster. GPG can verify the 28 megabyte windows installer file in just a few second (if that,) it takes me longer to type out the command.
If the dev team only published a signed list of checksums, I would still verify the PGP signed list, and then I would have to verify the checksums of the binary file. I would have to verify two files, which takes longer.