Cygnus should be a gold saint. I was never a fan of Dragon.
Dragon was the most popular Saint in Japan back in the 80s. Seiya was the least.
All five did reach God Saint level, but ultimately went back to Gold Saint level with some choosing to take the role. Gold Saints are not as free as Bronze or Silver Saints.
Plus, they could only become the Gold Saint if the Gold cloth of their zodiac sign was without a holder.
By the way, did you know all five heroes were in fact half brothers except for Phoenix and Andromeda who were full brothers?