I think CP Mete-Marit look ok. Could be better, but it is ok.
On the weight issue, which seem to bother quite a few:
Remember that a photo is adding weight to any person.
Also remember that CP Mette-Marit has worn quite a few light olors in Mexico, and those two combined doesn't make her neither anyone else look slim.
I see CP Mette-Marit in the white dress she wore on the Peace Prize Concert in December 2008. Whn I saw her on TV in that dress, she did not look like she gained weight. (Even though tv pictures also might add weight to a person.) The same white dress she has now worn in Mexico, and the dress doesn't seem to have gotten tighter since December -08.
So when speculation abpout weight gain for different reasons when you see pictures, look at the picture and try to see if there migt be any factors that might add weight to just any person if he/she was taken pic of at the exact same place in exact same clothes.
Please wait for an official announcement from the Royal Castle if the couple have more littel ones, and stop speculating.