I was told that the new USMC was specifically designed to get the bayonet back to what it was originally intended to be, a weapon. For too long, the military had wrongly considered the bayonet more of a field tool that could be used to spear someone, than a spearpoint that could also be used for simple cutting around the base.
With the longer blade, it does give an impressive profile. I would also note that quite a few third-world countries consider a smaller blade, like we all prefer for utilitarian purposes, to be feminine or not for a full-grown man. This might have played a part in the USMCs decision to lengthen their bayonets.