In fact, Kyoryuger is doing not a lot better. Usually a new show will get a higher rating. I remember someone pointing out that most KR/SS series get a high rating at first, but as the series progress, the ratings will start to decline before finally settling around their final ratings.
So in a way, I'm quite worried that Kyoryuger just have a bit more than GoBusters total ratings.
Even that is at least something of an improvement. From Go-onger until Go-Busters, there was a trend of each series having an average rating around half a point lower than its predecessor (with the exception of Shinkenger.) An average half a point lower than Go-Busters would be pretty disastrous ...
Go-buster is now ranked as the lowest Sentai in terms of rating. i doubt its successor will start off with a half way point lower, Toei would immediately cast another Carranger.....
Even when Wizard first aired it got nearly more 2+-% rating. while Kyoryuger only got 0.3% rise. Hope it can survive the mid season drop, however. I hope so