Right now there is about a 95% chance that when I manually review an agent's code I find nothing that needs changing.

I find it plausible that an extra agentic review pass and more testing can bring this number up to the point that one never needs to review code again. AI writes pretty good code nowadays.

(You still need to be diligent and decide the architecture during the planning, and read the gotchas and "things to note" that the agent will spit out at the end of implementation if it had to diverge from the plan.)