It's all about how much the gun weighs, how you mount it, and how well fits you. I agree that a 5 1/2# gun could provide more recoil than one might want under high volume. But, that's not it's niche. The lightweights are for carrying all day and shooting occasionally.
OTOH, add just a few ounces to the gun, make sure it fits you, and you can shoot an unlimited amount through it without a problem. My Beretta 687 SPII Sporting weighs 6# 3.9 oz, empty. I have put nearly 1500 rounds through it in six hours of shooting doves in Cordoba, using mostly 7/8 oz. loads, with no recoil issues. My shoulder would be slightly tender by late afternoon, but completely normal the next morning. And, the thing is, I can easily carry that gun all day in the uplands without tiring.
I'm with Miller. I'm amazed at the inability of so many to handle a little recoil, nobody here in particular, and, I might add, the inability to carry a gun that weighs over 6 lbs. I understand that heart surgery and other things can be extenuating circumstances, but I'm afraid we have become a country of pussies.
SRH