We don't know that is is "rock inspired" do we??
It could be a power ballad. OF course that won't go well for Miranda either (quiet, voices!)
We do have Miranda's comment to Associated Press
"We're really rocking in country music and we're coming together as a force," Lambert said. "To me, like, if you're sitting on the front row, you might want to scoot back. It's a force. It just feels exciting to me. I'm ready to rock."
--which strongly suggests that she thinks of it as predominantly Rock inspired.
Also, their previous live collaboration was Rock inspired.
Power ballads, I know, are very popular in this fan base, but, overall, Carrie's career suggests to me that she's drawn rather more to Country Rock. Pure power ballads like "Wasted" and "So Small" have actually featured rather less in her major releases than is sometimes assumed, and even less so more recently. I think the first "official" duet recording between the two leading female artists in "new wave" Country will be a high energy song - but more Rock influenced than "Diva" influenced.
Nevertheless, I think this will be a hybrid song, with a distinctly "contemporary" feel. Priscilla Renea is an African-American artist, with a background in R & B and ElectroPop.
The other two writers, Chris de Stefano and Brett James have worked more often with Carrie than they have with Miranda.
To me, that suggests a likelihood of two things - firstly, Carrie is highly unlikely to take a minor, supportive role, as you feared in one of your posts. And secondly, I think it will be a modern, market friendly, and potentially rather innovative sound.
And for those of you with a strong interest in awards, this could be a red hot favourite for Country collaboration of the year, both at the industry shows and at the Grammys.