Lighter would have been nice by 100 grams, but the Nikon D850 looks to be 100 grams or so heavier:
Nikon D810: 880 grams (unclear if this includes a storage card or a battery, probably not so not directly comparable)
Nikon D850: Approx. 1005 g/2 lb 3.5 oz with battery and XQD memory card but without body cap; approx. 915 g/2 lb 0.3 oz (camera body only)
Or maybe the specifications differ (with/without battery)? The D850 is 915 grams as body only, so maybe it is only 35 grams heavier?
No big deal with a lens anyway. And I’ll gladly take the 8256 × 5504 image size of 45.4 megapixels and may other feature improvements as a nice upgrade over the D810. Assuming the Nikon D850 image quality is better in all respects.