What's special about the 18-55? My old XTi came with one, except it is 3.5-5.6 while this new one is 4-5.6. Must be the motor type? Not all that exciting.
But it is about time to get a new APS-c - the T7 is looking good.
The old Rebel XTi came with a 18-55mm lens, good for 10 megapixel stills, but insufficient sharpness for the current 24 megapixel cameras.
The current 18-55mm F3.5-5.6 IS STM was a huge mechanical improvement, with very fast and quiet focus motor, ideal for video but has become bulky.
The new 18-55mm F4-5.6 IS STM is more compact, and should have lower manufacturing cost, although it is not yet known if the image quality will be as good as the current one.