Every time Mazda came up with a "new" rotary engine, they said they solved the problems of the previous ones. And they never did. It is like when GM says the new Corvette won't pop creak and rattle over bumps on cold days because they have solved those problems.
Some problems are just inherent to the base design concept, and the best you can do is minimize them, but never eliminate them. Wankel engines use lubricant oil. Fiberglass bodied sports cars creak and pop in the cold. Just the way it is.
But I applaud Mazda for trying, and I am happy to see them mostly out from under Ford's thumb. One of the best non-Volkswagens I have ever owned was a Mazda B2000. 404k miles and a deer is what took it off the road.