The RR event and the 787 battery fire both have fixes approve by the regulator. That makes them equal in the eyes of the regulator (nothings perfect)
Sadly, this is probably true. I don't thing building to regulations always results in a quality product.
But these problems are different in one significant way: For the Rolls engines we (Rolls, the regulators, airlines, etc) are fairly certain we know what the failure mode was and can make an educated judgment about the fix. But in the case of the 787 battery, Boeing admits to not knowing the root cause. Boeing and the regulators are confident that the fix will render further flights safe, within the regulatory definition of safety. And they have some theories about what is happening. But there is still a lot to be learned from in service performance of the 787 battery specifically and the 787 in general, should the root cause prove to be a systemic QA problem across a subset of their manufacturing. So we all watch, since there is still something valuable to be learned.