Complex sentence: Arizona Center was designed by the Rouse Company and opened in 1990 to great fanfare and high expectations, as it was considered one of the original components of the ongoing downtown revitalization efforts in Phoenix taking place since the early 1990's.
Split into simpler sentences: Arizona Center was designed by the Rouse Company and opened in 1990. It is considered one of the original components of the ongoing downtown revitalization efforts in Phoenix taking place since the early 1990's.