You don't want them to have such a flat top line, cause I feel they don't move as nice, but you don't want them to be so butt high for them to appear to have such a heavy front end. If they are older, and mature, then yes I see that as a confirmation fault.
When they are younger and they are growing, yes they will tend to look like they are a bit butt high, but usually they will grow out of it and will even out. Usually once they stop appearing to be such butt high that could mean that they have stopped growing by time.