Does this imply that Himawari's ability to use gentle fist is more potently dangerous than the average Hyuga?
No; there's two things going on here, and one is a well-known thing if you've ever been a parent or near a young child.
The first thing that's going on is that Himawari was able to subconsiously activate the Byakugan out of anger. This is not contested at all; she's seen with tears in her eyes as it activates due to her favorite stuffed animal being torn up.
The second thing is that, well...little children do not know how to control what strength they have, which can result in both surprise and significant pain at the point of attack. This could be innocuous like a quick slap to the face; this could be worse like being kicked in the bread basket or lower.
The main thing at play here is that the fact that Himawari is so young and that Tenketsu is such a potent taijutsu that it caught both Naruto and Kurama so thoroughly off-guard it knocked them out.