Michael Riedel is not a critic, he's a gossip columnist. He doesn't write reviews (although sometimes he tries to slip one in), he writes what's happening on the theatre scene. Chances are he didn't even see a preview and just heard from "a source" that Chenoweth and Hayes weren't getting rousing applause.
There could be two sides to this, one is understandable and one is, well, stupid. The understandable side is if Chenoweth is asking that the added scenes featuring the new songs be re-written because, as of now, they simply don't mesh well. That's understandable and is a concern for the sake of the show (as well as Chenoweth). Also, I understand the desire to make Fran a little more, well, memorable in the beginning. The Fran in Promises, Promises is different from the Fran in The Apartment. In The Apartment, there's a rapport between MacLaine and Lemmon that shows us a witty, warm, and lovable side to Fran, until we see the dark side of the life she leads. That rapport and that first impression isn't there in Promises, Promises. She sort of just comes on, comes off, comes on and then comes off until "Knowing When to Leave," where she REALLY makes an impression. Also, in addition to all of this, MAYBE Rob Ashford is realizing from the audience reactions that while there are some dark moments in Promises, Promises, it isn't ALL "Mad Men." There's a great deal of lightness to the piece.
However, if Chenoweth is simply asking for shtick so that she can go back to her comfort zone, then I've lost a great deal of respect for her. I would've had more respect for her if she made a valiant effort to do this role as is and failed, then try to conform the role to her comfortable shtick.
"Sing the words, Patti!!!!" Stephen Sondheim to Patti LuPone.