I wanted to post the famous 'Death of Superman' image with Lois holding Superman in her hands. But sadly i can't.
The poignant moment when Superman from Kingdom Come met Lois Lane after the aforementioned death in Convergence Superboy #2.
That same Convergence showed her becoming a mother.
She had long hair when she finally married Clark Kent.
As you can see there are a lot of memories with her in her long hair.
In my opinion, a woman looks most beautiful when she has long hair. If Lois keeps that i would love it too. While black hair is good, let her have brown or red hair. The color would differentiate her from Diana who has black hair. I prefer brown. And she can tie it too. Thus, she has both styles with her. Long flowing down her shoulders as well as varieties of hairstyles. In fact, when i picture Amy Adams i picture her with her hair tied up. It looks neat.
At the same time i prefer it the least for Lois.