Egypt & Nubia: Uneasy Neighbors

My only Observation: 

Why the Kushite monuments were poorly constructed?

Nubian pyramids were built by the rulers of the ancient Kushite kingdoms. The Kushites built these pyramids some 800 years after the pyramids of Ancient Egypt were built. They are thought to have similar workmanship of the pyramids of Ancient Egypt, but on a much smaller scale.

Nubia in the Nile valley lies within present day Sudan, was home to three Kushite kingdoms during antiquity. The first had its capital at Kerma (2600–1520 BC). The second was centered on Napata (1000–300 BC). Finally, the last kingdom was centered on Meroë (300 BC–AD 300).

Kerma was Nubia's first centralized state with its own indigenous forms of architecture and burial customs. The last two kingdoms, Napata and Meroë, were heavily influenced by ancient Egypt culturally, economically, politically, and militarily. The Kushite kingdoms in turn competed strongly with Egypt economically and militarily. In 751 BC, the Kushite king Piankhi overthrew the 24th Dynasty and united the entire Nile valley from the delta to the city of Napata under his rule. Piankhi and his descendants ruled as the pharaohs of the Twenty-fifth Dynasty. The Napatan domination of Egypt ended with the Assyrian conquest of Egypt in 656 BC.