It has been said that soldiers later in the war tossed their Colts to the sides of the trails when they got a Remington.
From an engineering standpoint the Colt is very poorly designed, so much so that I have to wonder what possible reason Sam Colt had for the cantilever design, as it has no advantages (Except in ease of manufacture) and many weaknesses. Weakness is weakness, and saying that since it was a BP arm weakness doesn't matter is baffling to me, why would one design a firearm to be weak?
What happened is that competition resulted in a superior design, which is why a competitive manufacturing world is good for everyone. If the open top design were superior newly designed revolvers would have them today.
Also, theoretically the Remington should be more accurate, not less, and if they are less accurate it has to be because of something other than the solid frame causing it. I suppose with the hammer back the sight length is slightly longer on the Colt, but the fact of the rear sight's tiny available area and it's movement should more than offset any such advantage.
Even Colt abandoned the cantilever frame later, long before smokeless powder came along, by the way.