Yes, English is changing. It always has been.
But No, this is not a change. It's been around for at least 300 years - I ran across an instance just a couple of days ago in a letter by Lady Mary Wortley Montagu from around 1717.
What you are seeing is not a change in the language itself but a change in the public use of the language.
A hundred or so years ago almost everything which appeared in print or was spoken in a public forum (aside from purposefully colloquial or dialect usage in fiction and plays) was very carefully composed and edited to conform to the most exacting standards of formal written English—in effect, public utterances were routinely translated into the formal dialect. But since that time three trends in particular have blurred the boundary between public and private use.
- The formal dialect itself has been extensively "colloquialized". Literary and latinate inversions are now eschewed, contractions (at least the "standard" contractions) are freely admitted, periods are briefer, and so forth. The best academic writers have discovered that it is possible to write in the vernacular without sacrificing clarity or precision.
- The rise of radio and television created a mass audience for non-scripted discourse, which inevitably led to a great intrusion of vernacular usage into the public arena. The stars of broadcast journalism today are not "literary" craftsmen like Murrow and Cronkite but colloquial improvisers like Limbaugh and Colbert.
- The rise of the internet put everybody's language into the public domain. Any Google search will display, on an equal footing with the "standard" uses, non-"standard" uses like that you cite—uses which would never have appeared at a time when the only existing mass medium was, linguistically, rigorously censored.
Objective Jill and I and Jill and me have always competed, with me historically dominating the public sphere and more or less holding its own in many private spheres. It remains to be seen what will happen in the newly globalized habitat: whether one will eliminate the other, or the terrain will be divided on new lines: it's entirely possible that future generations will come up with semantic distinctions.
Check again in 300 years.