haven't seen the video as I can't understand the language but I do agree and wish the abilities were interesting and reflective of her reign rather than having it to be the same as civ v version.
Keep in mind that only the Hwarang ability is unique to Seondeok. The other abilities (Three Kingdoms, Seowan, Hwacha) all represent Korea as a whole. So, it wouldn't make sense for the other abilities to reflect her reign in particular.