I agree with your concerns, although can also see that the creator deserves to be rewarded across platforms as they are contributing to each - so why not get "paid" by each platform. This is fair for good quality content (as some readers may not otherwise find it if they stick to say Steemit) but I agree that this would not be good for poor quality content that might then get pumped everywhere. Aaargh!
it is going to get messy :D
Indeed!