Based on those extreme choices, small and far, hands down. I would deal with the "difficult" sequences. I like the challenge of hitting smaller targets fast. Working on that skill set is my preference. My first choice though, would be a variety of target distance, spacing and sequences. Variety is interesting to me, but I also prefer the target sequences make sense. Shooting a goofy, overly difficult sequence "just because" doesn't make it fun.
Based on your own description of small, sounds like SASS recommended target sizes are considered "small". You stated:
"...pistols lets say anything equal to or less than 20x18 is small and for rifles anything equal to or less than 16x16 is small"
An entire two day match of nothing but "Big and Close and Easy" I'll stay home.
Interesting you chose such extremes, tying "difficult" to small targets and "easy" to big targets. Nobody likes P-Trap stages! That's kinda a slanted question isn't it?