One of the design goals of Zero-K is to have a prolonged period where winner is not yet clear and no side has an overwhelming advantage.
To achieve this in practice, it would be best, if there was some sort of "buffer" zone, where skirmishes happen and where small loss of land does not lead to slippery slope to defeat.
However current maps do not allow that, because they often feature prominent metal in middle, or uniform metal spread. So even small loss of land leads to permanent economic disadvantage.
This map setup is a relic of ZK predecesors that featured metal makers and moho mexes (BA, AA, TA) and it is not only not needed now, but I believe that it is directly detrimental.
It is especially bad on maps with central "uber" mexes, where team rushes to mid to capture it and often this initial state determines the outcome of entire game - defeat in slow motion.
Buffer zone, devoid of mexes would also put less emphasis on "central porc line" and more on army movement. There would be less need to hold your ground, you could do tactical retreat. Also there would be less need to defend central position (you could choose to defend closer to where economy is), without obstructing windmill lines, defenses spread everywhere and comms sitting in their "lanes" (big team games).
So it would be really great to have more interesting maps with "non-standard" metal layouts.
greater weight on metal around starting zone, gradient toward less and less metal towards middle (with no mexes around middle, to create buffer zone where fighting and retreats can happen without impact on mex economy)
maps with "hotspots" - areas with dense metal clusters. For example map could have 4 hotspots, besides starting zones, where mexes appear in dense concentration and nothing else.