Doesn't 3 athletics make it a bit hard to avoid kick+slash combo,
Or hard to cover your back against fast moving opponents,
Or hard to backpedal against multiple opponents,
Or hard to avoid being easy prey to cavalry?
It seems like it's only good for blocking entrances, passways which can be broken by kickslashes, crushthrough weapons or horse bumps (if it's not a siege most likely).
I find the other defensive sihelder guide more appropriate.