Saw this 28-70 f/2.8 review pop up. He compares to 28-70 f/2, 24-70 f/2.8, and 24-105 f/4, then against a number of primes. Tests portraits then landscapes. The comparisons show you shouldn't worry about losing the 70-105 range, as you get more detail on the 28-70, and you're better off just cropping. https://www.youtube.com/watch?v=By7RwR7oqZA