DC has always sortof... failed to understand what makes EDH work imo (but that's because EDH is perfectly playable between 2 people.) At an LGS I used to attend to, "French" became popular for a time, which actually impacted regular EDH in some pretty awful ways (players would jam their "French" deck because they lacked another deck, or felt that the French deck was more powerful than their fun EDH proper decks.) Consequently, that meant that the number of policing, combobreaking, or otherwise "Fair Enforcement" decks were in short supply (I would get dragged into EDH marathons because my brews tend to focus on combobreaking and encouraging margin/value based play.) This is probably the only period of enjoying EDH that I experienced a level of fatigue that made me just not want to touch the format whatsoever.
With that in mind, in EDH proper, we have the benefit of having our guidelines given by high level judges, instead of salty players' demands. I actually dug the banlist for French on my initial appraisal, because I think
Mana Crypt,
Mana Vault,
Grim Monolith and
Sensei's Divining Top effect the relative power-level of EDH far too much- but then I noticed the number of tutors banned, and I realized that it doesn't really want to embrace Highlander as a format. DC wants to balance itself as 100 Card Singleton Legacy, for people who probably just don't want to actually use the funds for playsets in a real Legacy deck.
Which brings us back to Breya. I have a hard time seeing her a problem without access to Vault, Crypt, Monolith, Top,
Chrome Mox,
Mox Diamond,
Mishra's Workshop,
Sol Ring,
Vampiric Tutor, or even
Loyal Retainers and
Treasure Cruise. This is quite simply a design philosophy of deck-banning, where it may have been more appropriate to ban
Krark-Clan Ironworks if Breya showed herself to be oppressive (because, I would wager that
Sharuum the Hegemon, and
Sen Triplets would be far more oppressive artifact generals if not for Ironworks + Deathmantle or similar looping)
Also lol, Tasigur is banned as a general. "It's strongish, we need to ban it"