Out of pure interest, I've compiled a list of the maps with the least random outcomes. This means I applied Whole History Rating to each of these maps independently and scored the accuracy of it. The better the rating system can predict the outcomes of games on a specific map, the higher the score. Maps with purely random outcomes are most unpredictable and thus earn the smallest score.
Sadly this requires a lot of games on each map to achieve usable data and even using the entire zk dataset (filtered for fair 1v1-3v3) proved insufficient for all but the most popular maps. Anyway I found it interesting to see that maps one might consider "random" are actually very predictable, probably due to a strong correlation between skill and players' experience in map specific strategies.
1. Red Comet (4551 games played): 0.067
2. Comet Catcher Redux (1208 games played): 0.061
3. SpeedMetal (1239 games played): 0.053
4. DesertCliffsV1 (1383 games played): 0.049
5. TitanDuel (2931 games played): 0.048
6. Archers_Valley_v5 (1710 games played): 0.047
7. DarkSide Remake (2160 games played): 0.045
8. Icy Run v2 (2269 games played): 0.043
9. Into Battle_v3 (1097 games played): 0.042
10. Ravaged_v2 (2086 games played): 0.042
11. Avalanche-v2 (1591 games played): 0.042
12. AlienDesert (1373 games played): 0.042
13. Barren (1257 games played): 0.041
14. Geyser_Plains_TNM04-V3 (1243 games played): 0.039
15. Small_Divide-Remake-v04 (4128 games played): 0.038
16. Aquatic Divide Revised v02 (1055 games played): 0.036
17. Trojan_Hills_v02 (1037 games played): 0.034
18. wanderlust_V01 (1320 games played): 0.033
19. SuperSpeedMetal (1420 games played): 0.033
20. Badlands (1291 games played): 0.032
21. Fields_Of_Isis (1404 games played): 0.031
22. Cooper_Hill_TNM02-V1 (1338 games played): 0.030
23. FrozenPlanetV3 (1017 games played): 0.029
24. Altair_Crossing_v3 (1410 games played): 0.023
25. Intersection_v3 (1280 games played): 0.023
26. Battle for PlanetXVII-v01 (1205 games played): 0.014
27. Vittra_v1 (1096 games played): 0.013
28. IsisDelta_v02 (1005 games played): 0.010
29. Small Supreme Battlefield V2 (1714 games played): 0.006