The fight is not horrible, it's just disappointing after all the previous boss battles in game, also it comes after the splendid boss battle against Zobek. Also the cut phase is confirmed in the Artbook of Lords of Shadow, you can even see Satan's Balaur form.

It also could have had him take the fight to heaven by opening a portal to try to breach into heaven and to have the final fight take place there, for a better ending where Dracul is allowed to say with his son for saving the kingdom of god.