You chose some really good errors. You are 100% correct on their failed HISTORY of prophecy. Watchtowerism is very simply TIME-PROVEN FALSE, not the opinion of disgruntled apostates but TIME all by itself is the factual proof that the leadership of the JW movement have NEVER had a clue about the future. This claim of knowing the future based upon Bible prophecy is their only distinguishing characteristic, their only claim to fame, the only reason to be a JW. If they (the JW leadership including the new GB) can't correctly interpret Bible prophecy then they are worse than useless because all their "wolf-crying" makes a laughing stock of God and desensitizes the world's population to any genuine apocalyptic warnings.
Keep in mind that I don't think there are any such things as Armageddon, Jehovah, Jesus, Satan, or a god of any kind but the point here is that I'm giving the benifit of the doubt by accepting the JW worldview that such things are possible. It is not about what apostates or atheistic opposers think, but rather it is all about the Watchtower leadership's own claims throughout their 130+ year history and of the resulting 100% failure at predicting any future events.
Very simply, there cannot be an urgent life-saving ministry for people who are warned of imminent Armageddon if they keep dying from old age generation after generation. Since all who were warned have now died without seeing Armageddon over numerous generations then there has factually been NO life-saving ministry since none were saved from a non-event that couldn't have killed them in the first place. If there was a God He would not "spirit direct" an organization to engage in such a self-defeating waste of time and energy which would only benifit Satan and his demons. This lack of any Armageddon is a HARD FACT and not a debatable point of disagreement.
The Flood is another logical conundrum for JWs. Not only is it 100% impossible by every scientific measure, evidence, and field but the whole idea behind it is completely insane. If you built a beautiful house (the Earth) and it became infested with cockroaches (genetically sinful humans and halfbreed evil angels-just for giggles-) would you flood it to get rid of them while preserving some cockroaches (Noah and his family) in a box (the Ark) to repopulate your house after it is drained and restored? What did you accomplish? Within just a short period of time the house (Earth) is over run again with cockroaches (sinful humans). Not to mention that an all-knowing god should have been able to conjure up the equivalent of bug spray to target the specific pests he wanted to get rid of without ruining his house by flooding. Heck, God should have just been able to make the bad pests disappear cleanly since He created it all to begin with.