A 45 with a long conical will take any game that walks on the planet cleanly. Feeling under gunned with one is like sayiong the 45-70 is a joke! The same can be said for most of the muzzleloading bores. My 36 with a 170 grain conical over 50 grains of powder will do for anything that walks this side of the pond with proper shot placement.
I have a 36, a 50, a 54, and a 12 guage right now. Most of the time I find either the 36 or the 12 guage in my hand. The 12 guage is top dog since I have a 50 barrel for it. It is just as usable from bunnies to elk. That is as close as I have come to a one gun solution. A guy with a 12 guage, a bag of balls and a snake of shot is just about as well armed as you can get east of the big muddy. West of it in the plains/mountain states, most want more range than a smoothy will provide. Longer shots and bigger game. The perfect gun there is something like Stumpy's 54 post. A true one gun solution with differing power levels for different uses.
The 50 is easier to buy supplies for, but the 54 isn't too bad either. They both cover pretty close to the same power levels. Close enough that what one can be used for, the other pretty much can do the same thing.
In the end, it would depend on where I was hunting for me. The 45 with roundball over a small powder dipper of powder makes a good small game load. If you pull the ball and add a second dipper of powder with a 450 grain conical. Now we are talking bears!. East of the Mississippi the smoothbore gets the nod. Out west I would likely choose the 45. Of course, there is a lot of wing shooting to be had out there also.
I can't decide!!!!!