The biggest problem is the idea that you can force a happy ending and simultaneously take one away. If Regina gets her happy ending (and Marian dies) then what about Marian and Roland? They lose their happy ending. Regina HAS done good things. She was on the path, it was fine. But now she’s trying to force fate’s hand, which is what she tells Sidney. She doesn’t want to work for it anymore, she wants fate to be changed in her favor. That’s cheating the moral system.
According to Adam and Eddy: Roland barely knows his mother. Does it make it right…no…but it is what it is. Marian’s fate was death….Emma intervened and messed up with fate leaving Regina once again to pay the price. Was Emma rescuing Marian not forcing fate’s hand….yes she was….Regina is merely fixing what Emma broke.
How much work does it take? Death? Rumple tried that. Sacrifice? Regina tried that. Nothing works….she’s all out of options. Regina had succeeded, she won, she became a hero twice! Right up until the moment that Emma brought Marian back, thus rendering Regina off her pedestal of victory. Fate was in her favor until Emma screwed it up!
"If you go as far as you can see...you will then see enough to go even further." - Finn Balor