Why would it be a can of worms? Other than a lot more recoil/velocity it would be about the same. Put a muzzle brake on it and it would kick less than the 7mm RM.
I'm having a 28 built right now. Picked up the dies and 100 rounds of 26 Nosler brass yesterday and last night necked the brass up to 28 cal and they are ready to go. I have the barrel sitting here (1 in 8 twist, 5R, #5 Krieger in bull sporter contour). The reamer is about 6 weeks out however. Nevertheless, I should have it at the range in about 3 months give or take. It will have a brake as I expect to be running in the 3,800 ft lb area which is a bit brisk if you want to be able to spot your own shots.
You can rechamber the 7mm Rem Mag to 28-Nosler. Though the factory 24" barrel can be improved upon.
You can rebarrel to 28-Nosler. A nice 26" barrel will make the 28-Nosler sing.
You may have to work on the bolt throw and magazine but this is a long action so it should be strait forward. Might be DIY might be smith level work. The action can do 300 WM so I believe it can do 28-Nosler.
I sent a Ruger Mark ll that was chambered in .338 to fierce arms last January. It took about 6 months to get it done, which they'll tell you up front. 28 Nosler, 26" carbon fiber barrel with a fiberglass stock & muzzle brake. At first it shot horribly with Nosler factory ammo but I finally got it to shoot 139 GMX with reloader 33, 5 shot group .625. With fierce's muzzle brake it has very little kick, maybe like a .243. On the down side it's as long as a goose gun and I can't close the bolt with 3 shells in the mag. Absolutely love this gun and Courtney at Fierce arms was real good to deal with and wasn't that expensive.