The recoil difference between the 300WSM and a regular 300 Winny is negligable. The two main differences are the ability to use a short action with a short bolt throw which translates into a few microseconds faster reloading rate and the short, fat powder column which has served benchresters so well in the 6mm ppc and the likes. I personally have shied away from the WSM and Rem SAUM's as I did not like the way they fed in the repeaters that I handled. Unless you handload, these newer magnums are harder to find ammo for that the regular 7mm and 300's. I feel that muzzlebrakes are for extremely speciallized rifles because of their HUGE increase in noise. If you shoot a muzzlebraked rifle without hearing protection, you WILL cause damage to your ears.
If you think recoil may be an issue, I would recommend trying a 270 or 280 and see how that feels for her first- this is often about as much recoil as many people can tolerate. Most of what you have read about the short magnums is exactly what you charaterized it as- Hoopla.
All this said, If I could find the right rifle that fed and shot a WSM to my liking, I may have one built myself.