An underrated focus of Metasploit was making defensive tooling more robust. Spoonm's work on SNG (as well as other payload/encoder randomization efforts) was effective at killing static (and arguably ineffective) payload signatures. You can find a related talk on the IDS/protocol side at:
https://speakerdeck.com/hdm/thermoptic-camouflage-total-ids-...Source: co-speaker of the OP referenced presentation