> For example, the fact that presentation and application are separate layers, and that compression/encryption are better in their own layer (presentation) rather than totally integrated in the application.

CRIME attack enters the chat

Compression is not better in its own layer. See the CRIME attack on TLS compression.

Encryption is better at as low an end-to-end layer as possible so that we can have a hope that we can off-load the work to hardware.