I think filters drain back so when you start them cold you don't blow them up. Also when the oil is thick on start up, it will bypass the filter till it warms up and thins a little bit.
Also, the number of pleats can be anywhere from 35 or so all the way to over 60. It means almost nothing, untill they start to get too many pleats and they start to pack them into the cannister too tight. Every corner of a pleat really can't pass much oil. What counts is the width and length of the filter and its compostion, which could be paper or synthetic or a combination of both. This makes it difficult to compare them.
Some filters have thicker sides than others, and some have thicker bases than others. I am unaware of any filter that has both a thicker side and thicker base. They run within 2 or 3 thousanths of an inch anyway.
Some other things that need to be considered:
Length
Outside and inside diameter
End cap type
Bypass valve type
Anti-drainback valve type
Element types
Gasket types
Hydrostatic burst pressure
Filtration efficiency
Might as well throw price in the mix also
Some things are obvious when looking at a pic, but not every thing.
One thing is certain, most of them are all made by the same two or three companies, they all meet manufacturers specs, and they all sacrifice one thing or another in order to gain the upper hand and still be competitive.