What are the possible ten maps with highest creativity metric (CM) for most popular Sokoban families: Sokoban, Sokomind, Multiban? Or at least, 10 maps with high difficulty?
There is a site which compares maps in first column (CM and D): http://whirlio.com/doc/whirly_and_sokoban.htm
The principal metric adopted there http://landkey.net/gio/gio/diary/b1/doc/creativity_indices.htm is not a path length, pushes, or box-changes, but so called "creativity metric". In plain words, it is an attempt to go further than flat difficulty.
Note, that huge maps like: www.sourcecode.se/sokoban/levtext.php?file=Mastervip.slc or in Sokoban competition sokoban.ws/current_comp.php are unlikely will give highest CM because metric will be heavily penalized by the number of cells. (But probably will give high "flat difficulty = p + i + reint".
(For classic Sokoban, so far, "the winner" is "Flying Idea #132", by Evgeny Grigoriev, but this is perhaps because of insufficient research or used non-optimal solution.)
If you have a map with solution, but don't know its parameters, here is how to automate calculations: landkey.net/gio/gio/diary/b1/doc/creativity_indices.htm#calculate
(It seems, Sokoban deserved to have a separate tag in this forum ... can some member create it?)