Franchise Killer: The overwhelming mediocrity of Star Force 2 ended the popularity of the .exe verse, the last popular Megaman series, in Japan. They got their act together for the third installment, but sales didn't perk up. Not much funding at all was allocated to Operation Shooting Star, an attempt to uncancel both series that might've worked if it were a proper remake. A sad fate for the franchise that had its iteration of Mega Man as the face of its 20th anniversary.
The names of each of the zodiac bosses, their designs, and even the concept of astronomy-based foes actually comes from a Chinese only game called Rockman Strategy. Taurus, Cancer, Libra, and Apollo share very similar designs with this game. While big and covered in red armor in both games, Strategy!Taurus actually had his proper zodiacal element of Soil (compared to Taurus Fire's, er, Fire); both Cancers were naturally water-based; Strategy!Libra had the Wind element (Libra Balance is Non-Elemental boss that uses both water and fire attacks, and has an informal association with the Break attribute, rather than Wind); Apollo Flame and Strategy!Apollo are so similar in design you could argue that the first is an Expy. No link between the moon god Luna of Strategy and Miss Platz, though.
What Could Have Been: Star Force 4 was in the works, but they were informed they had to wrap the games up with 3, leading to the ending.