I've had two different questions come up recently about the same sweater silhouette pictured above. Question one was regarding what figure type does this sweater flatter? Some Knitters think that the way this garment hangs is very flattering due to the long diagonal lines that the front creates. Others think it makes the wearer look heavy, and wanted to know how to determine if it would look good on them. In terms of figure flattery the long diagonal lines should be flattering, however for this silhouette the factor to consider is the fullness of the torso. If your torso curves out away from your spine it is unlikely to make you look your best. If you have a midsection that is straight and perpendicular to the floor the garment tends to drop from the shoulder over the bust-line and hangs straight down. There is a space between the wearer and the sweater at the front. It therefore can take advantage of the long diagonal lines, especially from the front view. On a rounded torso the diagonal line advantage is canceled out by the viewers tendency to see relationships of the body to the garment. It can look like the garment is too small and is pulling open because of a sizing issue. Remember that the pattern photo has been taken on a tall, very slim model which is why most Knitters do not foresee this potential problem when they choose the pattern.Your posture can also have an impact on the amount of space between the garment and the body so assess by looking at both your front and side views in a mirror.
If you have already made something like this try wearing it with a darker garment as an under layer. The torso is more likely to look as though it is receding and that will make the wearer look slimmer.
The other question has been "Why is the schematic wrong?" The schematic is inaccurate due to the technical execution of the garment. Every one of the examples that I was shown was a pattern with garter or seed stitch borders that had been knit at the same time as the garment. These stitch patterns make great borders as they lay flat but typically they do not match the row gauge of the body of the sweater. That means that the border is longer at the outside edge than it is at the side where it meets the garment. If you want the fronts to hang straight, a border that is picked up and knit separately or knit and sewn on will work better. Normally you would work with a smaller size needle when creating the bands separately. An alternative partial solution would be to slip the first stitch of every row to tighten up the edge of the border, that will stabilize the edge but it is still going to be longer than the garment.
I have one more slightly fiddly fix. You can still knit the border at the same time with a set of smaller DPN's, (be sure to choose a non-slippery needle that won't slip out of the work). It will create a firm edge with no join between the band and the body of the garment. It means that you will switch between your regular needles and the band needles as you reach the borders of each front section. Just let go of the needles not in use, in the same way that you would in a circular project with DPN's.
To determine the best possible choice of size for the DPN's.... you need to do a swatch. But you knew I was going to say that didn't you?