I guess they finally decided to do something about the dry, gristly steaks that we got there in 2002 and 2006.
In my experience, many people are often disappointed when they have expectations like that. I don't see any clear indications that lots and lots of Epcot guests were clamoring for the opportunity to pay $39 for a filet mignon rather than paying $35 for a filet mignon, even with a quality-upgrade. Most comments I hear, about Disney Dining, especially IRL, is that things are
too expensive, rather than not expensive enough. :\ If anything, I think the issue is that those two menu prices (one from Bistro de Paris, the other from Le Cellier) are getting too close to each other, while leaving Le Cellier a 1TS restaurant. A beef filet at Rose and Crown, for example, runs $24. So Le Cellier is, effectively,
already a Signature-level restaurant, but they're simply not charging
DDP patrons the Signature-level "price".
So you should expect a very minor upgrade, just enough to be able to point to a few things that have changed, but nothing "major" at all.
While I agree with you that Le Cellier is most overrated restaurant, I think that that's not the issue here, but rather, as I mentioned above, the menu prices are.