The way I see it is, is that Nero changes some event prior to TOS (such as destroying the USS Kelvin). Events are changed somewhat, such as the way that Kirk encounters Spock and the crew all get together. The destruction of the Kelvin to a "superior enemy vessel" may have prompted Starfleet, to construct an advanced form of cruiser, such as the JJVerse Constitution Class.
Other than this, at current we can't really know much about what changes are done to the TNG-era and beyond. I doubt the destruction of a single ship, and the advancement of another ship would make the TNG-era (and DS9/VOY) drastically different, if any from the one we know.
Bottomline is, I prefer to wait and see the movie before making judgement on what just happened

PS: "General" Worf from the comic back may or may not have been killed in "our timeline", but if things remain changed after Nero's travel into the past, Worf may very well still be alive in the 24th century, in the "altered timeline".