RE: .270 vs. 7mm Rem Mag
In the same weight and model rifle, the 7mm will have slightly more kick. To me the difference isn't enough to worry about.
As far as "too much" I've never believed in being over gunned for anything provided the shooter can handle the recoil and blast. If you can handle the 7mm Mag, it will make a super whitetail rifle. I hunted with one for several years and killed a number of deer with it.