As a quick test I tried one exercise to see if it would work. The ‘Dotted Rhythms’ exercise helps you to play scales more evenly, accurately, rapidly and with better articulation. I first played all the major scales using the dotted rhythms pattern, left-hand and right-hand separately, and then played them again the usual way, with a straight rhythm. The improvement was immediate. I then played the same scales hands together, and experienced similar improvement. Quite remarkable and mysterious.
Edit: And it works too with fast passage work! I just tried it with a couple of Hanon exercises.