Ou Yangxun's European-style calligraphy is "precipitous". What does this mean?

Ou Yangxun summed up eight methods of practicing calligraphy, namely: "Like a falling peak, like a crescent moon in the sky, like a thousand miles of clouds, like a dead vine living forever, like a pine tree hanging upside down, like a cliff, like a crossbow on a thousand horses, like a sword breaking a rhinoceros horn, like a brush."

Looking closely at the European style, the brushwork is steep and vigorous, but the structure is balanced and the statutes are strict, showing a dignified state as a whole. However, Wanshou thinks that Ou Yangxun's cursive script is more "precipitous" in both brushwork and structure, such as Montitie in Zhong Ni.

His son, Ouyang Tong, is famous for his "learning from his father's calligraphy". His masterpiece "The Monument to Master Daoyin" is vigorous, steep and timid, but its exposed edges and corners also contribute to Ouyang Tong's calligraphy characteristics. Why did the Qing dynasty call this monument "dangerous and firm, born with peace"?

Therefore, Wanshou thinks that Ouyang Tong's precipitousness to his father is not precipitous "excellence", but precipitous "surplus", which is really undesirable.