You know, I thought this might be true for a while, too. My current map pack is 450 maps and 7 GB. I still download more maps to play Zero-K. In the past week I've played 6 maps that I didn't have before. So yeah, people are still playing on new maps all the time. A big part of this is because Jasper has been taking time to sort through them all and filter out the "good" ones to be selected by autohost.I do not see the use for such all-maps pack. Did you sort out some maps or it basically everything that is on springfiles?
I think a mappack with some 10 to 20 selected map might be more usefull. Have some diverse maps from (1v1 to 12v12, land,sea,large,small,...) so players have a starting point.
Why is Zero-K different? Maps that play like crap on many mods are viable for ZK. ZK is much less terrain-dependent. You've got a spiders lab, hover lab, amphib lab, jump lab, gunships lab, and planes lab, and ALL of them are viable starting labs. Maps that would be porc-a-rama in your standard *A mods play a bit differently for ZK.