>Opera was sane: it did not reload a tab unless you asked for it. It just reopened everything from cache
No. That is NOT sane, normal, or desired.
Webpages are live. If I want to look at a chached version, I'll save the webpage locally. If I'm pointing a browser at an address, I expect a current webpage. If it takes all of three seconds to give me that, I think that's okay.