After few tests I must say that dropdown with list of revisions is really confusing. If I create a post, and then edit it once, I have 2 revisions: original posts and version after edit. On GitHub in dropdown you have two entries, where first is labeled as "created" and displays diff between nothing and original post:
In your plugin there is only one entry:
And when I click it, there is no "revert" option available (it seems to be a bug). Since you switched from "diff approach" to "revisions approach", wouldn't be better to display revisions in similar way as GitHub? Then it should be more clear what is the target of "revert/rollback" and "delete revision" features.