I don't really agree. Aside from how it handled frontend code, changes in Sonnet did not truly impact my overall productivity (from Sonnet 3.7 to 4 to 4.5, i did not try 3.5). Opus 4.5/Codex 5.2 are when the changes truly happenned for me (and i'm still a bit distrustfull of Codex 5.2, but i use it basically to help me during PRs).