@FillionAphile I love MMA, and I love analogies so I’ll give one here.
I’ve been to jiu-jitsu classes and watched smaller, less powerful people submit much larger and stronger opponents. That was from one person being years ahead of the other in terms of knowledge, skill, and fight experience.
Halo was powerful, true. But we watched her resurrect more than once because we saw her make more than a few mistakes that cost her her life. As powerful as she was, she was prone to mistakes. She was also susceptible to mind games, something we witnessed her fall victim to. A weakness Nightwing would definitely recognize as a flaw to be exploited.