I think peaks are always rounded in Moho. For me, that's not typically an issue because strokes are rarely drawn thicker than a few points, plus I think sharp peaks can look over-long and weird at acute angles, but I do see what you mean.
I guess if you really needed a sharp corner at that scale, you could make it a fill shape instead?
Sorry, I know that's not what you're asking for but I think this is the only way with the current tools.