Its a compromise. I recon the only time a longer knife would be vaguely helpful is bleeding a red deer sized animals - you can gralloch with any length of blade. But I find carrying a knife over 4.5 inches a bit of a pain - they don't fit in pockets, the sheath digs into you when driving or crossing fences.
Yes you need to bury a 4 inch knife to the handle to bleed, but your hands and knife will need a clean anyway, so I don't think it is a problem. The knife I carry now is an enzo necker (2.7inches) in flat grind and have bled fallow and red with it.
By all means buy a few Mora knives and experiment. You can never have too many knives and moras are cheap, strong and good for larder work such as gutting off head and feet.
I cannot get scandi grind knives razor sharp for toffee (yes I've watched all the youtube videos) whereas flat grinds sharpen up very quickly on my lanksy - but that is a different matter!