We share similar "circumstances" in our need for less deer now, but even in the days of 8-10 a year I was still more of a small game hunter in days afield. We're blessed with no closed season and no bag limit on snowshoe hares, and an 8 month ptarmigan season with a 20 bird limit, as well as a 4 month waterfowl season with generous limits. Certainly the biggest factor in my choice of which species to hunt is weather. We don't get many nice days, and often have to contend with wind or rain and their influence on the game, as well as the hunting conditions.
Throw it all in a box and rattle it around real good, and your assessment of the utility of smoothbores is a perfect fit. We can legally hunt ptarmigan with rifles and handguns, and I've done my share of it. But even when they're sitting and willing to allow head shots, it's a whole lot more fun to stomp your foot and make them fly. Snowshoe hare and rifles are a terrific combo, but with the thick brush and the influence of weather, often as not they're on the move when you first see them. Basically if the weather is too bad for hares or ptarmigan it's perfect for waterfowl, and if it's too good for ducks, it's perfect for the others.
I've got a "smooth rifle" in a TC Renegade with a 62 cal Green Mountain barrel, and I've got a Brown Bess. Both get the job done, but I have to say a true shotgun (and especially a double) is a lot more satisfying and versatile in terms of balance and swing for quick wing shooting. I'm yet to own a fowler so I can give it a workout and see for myself, but it's hard to convince myself that I'll find it as versatile as a double.
Hunting is but one of my excuses for time in the hills, and more guns leading to more hunting is certainly a worthy goal. Anything that adds to the days out there has to be a good thing, doesn't it!