If 28s will fit (many road bikes have very limited tire clearance), then give it a shot. I run 35mm tires on the front and 38mm tire on the rear of my touring bike and it works great.
Unless raising your rear by a couple mm somehow negatively alters the fit of your bike there is no reason not to.
The strategy on mountain bikes BITD was to run a fatter front tire than rear tire to soften the ride for your hands and arms.