Fair enough, but also worth pointing out that IHG Diamond Ambassador and Accor Plus Gold are not exactly apples and apples.
I think a lot of the positive experiences at IHG properties would be more from holding Diamond than Ambassador, and similarly if you were Accor Plat (or Diamond) you'd very consistently be successful with early check-in, late check-out, and usually decent upgrades too - going off my own experience and those in the Accor elite treatment thread.
The problem with Accor Gold is that it's given out like candy (e.g. Anyone holding QFF Silver or better was eligible last year, and Ibis business subscription also come with it for $147 AUD per year) and as the saying goes - if everyone has status no one has status. It'll probably get worse now that Accor Plus members will start the year with 20 status nights, making Gold reachable for them after just 10 nights.
There is a really significant jump in how properties treat you once you jump from Gold to Plat though.