I personally think these are all positive bans. It's unfortunate that bans are needed every cycle lately, but these are all good ones to me.
Breach is a card that should never have been printed. Yawgmoth's Will was already insane, and printing the same thing for 1 mana cheaper was a huge mistake imo. This is just now finally catching up to reality. There was talk of banning Mox Opal but I think that is too premature when the obvious issue right now is Breach.
Sowing Mycospawn should never have been printed. And Troll was enabling too much efficiency for Blue/Black decks. I think both of those were the right hits right now. I know there's tons of talk about banning Reanimate, Daze, Entomb, etc but these are absolutely the right hits for now in my opinion. I think waiting to see what a format without Troll looks like is better than hastily banning any of the core cards. I'd like to see Bowmasters gone next.