You're right; it looks like a few of these features like the max range directive were also included in 1.0.
Bug fixes and security patches are applied to both stable and dev branches. Some of the recent buffer overflow patches only affect features added in 1.1.
Hopefully future changelogs can be more comprehensive and usable now that nginx has venture funding.
Also, I think there are bugfixes (and maybe security patches?) in 1.2.x that weren't in 1.0.x.
I'm just surprised that there isn't a coalesced list of changes for going from stable->stable release.
If I was in wide production, I'd want more guidance on what changed, and when I should be upgrading.