I was with you until you said Marvin Gaye. Lol. But I agree with the first part. She doesn't have range, but she's like Jhené Aiko, Ciara, and Aaliyah. They aren't traditional R&B or pop vocalists. They're more hip-hop or trip-hop. It's not about vocal gymnastics. It's about harmonizing and kicking melodic flows over dope hip-hop beats. At least, that's what it is when they're at their best.
I used to have Serius beating Mook by a lot more. After revisiting the battle many times, Mook's performance fares much better. They approached the battle with completely different styles/angles so it's difficult to judge. Serius had few bars, but lots of personals, rebuttals, jokes, and freestyles, while Mook had a lot of bars and jokes, but almost no personals or freestyles. In the end, I still give the battle to Serius.