Could be, yes. Although I do wonder if the average octopus suffers more when being killed than the average cow. If so, then I wonder if that relates to intelligence or to other factors. Structure of nerves etc.

If an octopus wasn't able to feel anything, it would again be okay to eat it? Or if it was sedated before killing it, would that change anything?

Lots of open questions I guess, but I'm just brainstorming a bit :)