My dad has a Spanish American War Colt 45.
Squeezing rounds off that pistol requires serious effort and affects your aim.
I've only shot 22 caliber semi pistols.
The trigger on a semi-auto is much lighter, the fire rate is two or three times faster, and there's no hammer.
Is that not the case on large caliber semi-auto pistols?
Trigger pull has nothing to with the presence of a hammer. And no, it’s not the case. Desert Eagles, the entire Colt line, most Barettas, Walthers, etc all have hammers.
The trigger pull was difficult on your father’s long Colt because you weren’t doing it right. To accurately shoot a revolver, you cock the hammer with your thumb and then shoot. When shooting that way, the trigger pull is a fraction of what is when you use the trigger to rotate the cylinder and pull back the hammer.
Oh, and fire rate has a lot to do with caliber. I can squeeze off .22 shots as fast as my finger will twitch. A Desert Eagle in action express, not so much.