forget the weight of 4 additional spokes per wheel
This will be negligible when youre using heavy shimano hubs. I can't think of a situation where 28H could ever be the best option. If you want a light/aero race wheelset you'll be using 20/24H, if youre commuting on training 28H will just be weaker with no noticeable benefits. Aero and weight between 28 and 32H is minimal but strength and stiffness suffers with 28H
This will be negligible when youre using heavy shimano hubs. I can't think of a situation where 28H could ever be the best option. If you want a light/aero race wheelset you'll be using 20/24H, if youre commuting on training 28H will just be weaker with no noticeable benefits. Aero and weight between 28 and 32H is minimal but strength and stiffness suffers with 28H