The new 17-70 f/2.8 from Tamron will be for crop sensors, sporting 16 elements in 12 groups, and weigh in at a hefty 1.2 pounds. It’s a lot of glass for a crop lens. It is designed for the Sony E-mount.
It has 9 aperture blades, indicating Tamron is set to position this as a high end version of a full frame 24-105mm lens, but for APS-C sensors.
The aperture can be set down to only f/16, showing that it has been designed for high resolution sensors that don’t benefit from further stopping down due to diffraction.