If Merida are smart, they had their design guys sit with Dennis, ask what he does and doesn't like about the bike and go back to the drawing board.There is hardly anything Merida can say to make this situation any better other than pretending this never happened.
Edit: Well they could blame it on the helm/wheels but no legitimate company would ever do that.
It's not like manufacturers haven't done this in the past, and they can even turn it to their advantage - "The new Merida Warp TT. Co-designed with World TT Champ and TDF Stage winner Rohan Dennis..."