I have been working on an asymmetric map layout for the last 2 weeks are so and have been giving it alot of thought during that time.
Obviously, the big issue with asymmetric maps is balance. i agree that it is almost impossible to reach the same level of balance you can achieve with mirror maps, but i think you can get close to it. it just requires alot of work/planning/testing.
Now if you look at sc2: there is 3 races, each has it's unique units/techtree/playstyle - because of this fact alone the game isn't 100% balanced, will probably never be and there will always be people whining and complaning about it. but i believe this is also what makes the game more interesting and successful than most other rts titles out there.
the different mechanics for each race, however, make even mirrored maps also unbalanced in tvz, zvp and pvt. for example, i think most will agree that a close position tvz on meta is far from being a balanced matchup. because of different race mechanics, all maps at least require players to adjust their game plan/playstyle to whatever spawnpositions you get. the only matchups where this isn't the case: tvt, zvz, pvp mirror matchups.
i was thinking about why it is widely accepted to have map/spawn position dependend imbalances in mixed matchups - it is even considered to make certain matchups more interesting to some degree. however in mirror matchups this has been pretty much nonexistent. a tabu? why not have a tvt matchup on an asymmetric map where spawn positions favor different builds for each player. like, have one terran with a more vulnerable natural but a closer third than his opponent. one might go for a more mobile army while the other might make more siege tanks, etc. those are just examples..
in my opinion, i think an asymmetric map can be balanced to an acceptable level. in fact, maybe more balanced than some of the mirror maps are (like the close pos meta tvz i mentioned above, or tvz on scrap station anyone? but the almost perfect balance of mirror matchups would be lost.
there are already alot of maps with rotational symmetry, which are also technically unbalanced unless you spawn cross position. recently, 3player rotational maps have gained alot of popularity - which are even a little more unbalanced than regular rotantional maps as you cannot have idendical terrain for each side - the game is designed for 45degree angles, 60degree angles just don't work that well :D especially ramps and chokes will cause alot of trouble. but testbug has proven that it can work and 3player maps have gained the acceptance of the community. granted, there is a huge step from 3player maps to completely asymmetric maps. but i believe once someone does it successfully there will be alot more coming. i would love to see more mappers and players give it a try. personally, i think that asymmetric maps can make matches even more interesting as they allow for more possible scenarios, more ways on how a map can be played.
i was wondering how others feel about about this topic. what is your opinion on asymmetric maps? do you think it could be played even on a competitive level? maybe only for lower skill levels?