Repetition sure does help. I kind of do the same thing that you mentioned. About one carving looking so different from another. I do a lot of Santa ornaments carved from Basswood eggs. Each one is different. They're recognizable as the same but, they're definitely different I've been carving for about 12 yrs. so I don't think it's improvement so much as I just don't go at it the same way twice.
My friend that helps me with my carving, has been carving for about 25 yrs. He carves a new design of Santa every year. Normally 50 or more. They all look much the same. Not identical but, really close. He can carve something from a pattern & it looks very much like the original. If I do that, it for sure doesn't look like the original.
I think I just don't pay attention to detail! Oh well. It sure means variety.