Depends on how it's used. A compressed grav pulse can be blocked or dodged. A heavy gravity field like the one used on Gladiator's cousin will merely slow her down and not take her out, etc..
That field wasn't heavy. That field was done by Robert Rider, Richard's brother, who had only been a centurion for a short while and has very, very limited access to the Nova Force.
One by Richard Rider, Nova himself, with all his experience in manipulating grav pulses and with the backing of the nova force inside him will definitely make her brain bounce about in her head. I don't think WW can stay conscious.
I can think of him doing a single gravity pulse to KO Moonstone, but that's basically a bolt that WW could block or avoid, it's hardly an insta win there. He still uses grav pulses like *bolts*, it's not like he can just think and make it happen, and that's something WW is quite capable of defending against pretty well. Heck, her forehead is protected by an unbreakable object too and her brain's a lot more resilient than most too.
Also, he specifically said that what Robby did is very difficult and he'd have trouble replicating it even with his greater power.
I know he said it was very impressive considering Robert was new, but I don't recall him saying he wouldn't be able to do it.
Plus, we all know Nova doesn't like to kill people unless he has no other option. A serious and heavy pulse from the Nova Force would kill moonstone. If he knows just how powerful WW could be, dont you think he'd up the ante? (So to speak)
__________________ Can you see me, Shalla-Bal?
I'm Flying!
I'm flying...
I'm...
Exact words, "I'm Nova Prime, buster. I pack significantly higher levels of nova force. And I'm telling you, I couldn't have done that."
"Oh come on."
"Seriously. I couldn't have pinner her line that. And I can explode super-star destroyers by coughing. It's not the nova force, Rob. It's what you do with it. I've never known anybody to weave, shape or manipulate gravity fields with the finesse you do. Worldmind says that in six generations, she's never seen a centurion with the intuitive-force skills you've got."
Richie's a lot more powerful but that kind of thing requires a lot of finesse and intuition apparently. He has his own tricks like the pulse he used on Moonstone, but precise control over a sustained period to keep someone that strong pinned is apparently really difficult. So it's not like it can be done to set up an easy pulse to the head, when it requires a lot of concentration to just do the field in the first place.
He can blast her strong enough to do real serious damage, but it'll be, y'know, a blast he needs to hit with. It might hit, it might be blocked. It might take her out if done strong enough, it might just rattle and stun her but not be a win. It's not a sure win, "Use then yawn" like some posts were implying.