Even though the basic approach of Litvak yeshivas is based on the Gra, it seems to me that that is  a bit too undefined. It would be better if there was a straight commitment to follow the Gra.

This way there is also a sort of protection against the Sitra Achra.

סביב רשעים יתהלכון "The wicked walk around the holiness". That is,-- the Dark Side is always going around places of holiness to see if they can find a crack to slip into the place.

[I should admit here that I am no where near following the straight path of Torah of the Gra. But I feel words of advice that might help others to walk on the straight and narrow are good-- even if I am not able to follow that path myself.]