Of all my years of research, you're the first person I've ever heard say that. I know that if you can find one of the rare-as-hen's-teeth 7 1/4" sure-grips, it can help with durability, but even slanters regularly blow out their 7 1/4"s when they start to add power (according the folks over at .org). My long-rod 225 is already making a lot more power than stock. I figure the lower gears, the planned T-5, and further upgrades will eventually toast the 7 1/4" in my Swinger, and I'd rather build in some insurance and add a lower ratio.
My only personal failure experience is with my 273 2bbl '67 Dart, totally stock. The current 7 1/4" rear howls like a banshee. Regardless, I'll likely swap the Swinger's rear into the '67 when I install the 8 3/4" in the Swinger, just because it's free and, thus far, quiet.