probably no advantage. just thinking about trying 28mm to see if the vibration is cut off the front end some, the rear is not the problem. if 28mm works in front, then the rear will wear out in time and need changing. good time to change to 28mm.
this would also be a good time to try different brands on the front without changing tires on the whole bike which may be disappointing.
at the moment i have quite a few 25mm tires on the shelf so really don't need tires, been hoping to tame my road bike vibrations some. 28mm may just do it. no doubt many here have a few skinny tires on the shelf, so how to make the best of it perhaps is to experiment with the steering a bit.
There is more to comfort and handling than just tire width. True, going up a size in just about any tire will allow you to run less pressure and give a bit of road vibration reduction, but the construction of the tire is just as important. A supple sidewall and good design can make one 25mm tire ride much better than an inferior tire of the same width. I run Bontrager AW3 Hardcase Lites and am very happy. I used to use Bontrager H4 Eco (no longer in production) on my hybrid mutt. They were decent utilitarian tires for mixed surface riding but had nowhere near the comfort and handling qualities of the AW3s. Even your rim width makes a difference in the profile and volume of the tire. My first road bike was a 1990s Trek 1500 with some of the narrowest rims I have ever encountered. The bike was designed for 23mm or less tires and, with it's early aluminum frame, could render your hands completely numb within minutes, even on relatively smooth roads. Squirrely was an understatement on anything less than perfect roads. I'm much faster on my current, cro-mo framed road bike, thanks in great part to better handling and more confidence from better and wider tires and rims.