I have seen one person tear a hamstring due to getting their foot caught in their partner's hakama. To be fair, though, they were too tight and rigid with their ukemi and that's what caused the incident.
I can understand the Shodokan sport activities not wearing hakama. We do not do the kiyogi tanto randori so it's not an issue. Our folks often wear hakama or not, depends on the occasion. Our randori (slow and intense at beginning stages but fast and full force at higher levels) has not been hampered by hakama even when we go to the ground as necessary at times into newaza. I don't think it really matters what you wear. You need to learn to work within many different settings, etc.