Note

Ground/Air Rush Distance : Travel time in seconds measured by a Worker/Banshee between the tops of the main ramps
Symmetry : ↔ (reflectional symmetry), ↻ (rotational symmetry)
✓1 (At Eternity's Edge) : Line-of-sight blockers are placed in the main base (Metalopolis-style).
✓2 (Blackrock) : Some high-ground pillars are landable/climbable/buildable. [relevant reddit post]
✓3 (Old Sun Temple) : Vertical spawns are disabled, so the enemy base is either at the horizontal or cross spawn location.
✓4 (Storm Surge) : The central water area is passable but unbuildable (common feature in BW, but rare in SC2).
✓5 (Voidstorm) : Some mineral patches are scattered around the map. These mainly act as a nuisance against Terran walling with CC/OC/PF, since these buildings cannot be placed near resources. Also, there are mineral-only mini-bases in the corners.
✓6 (Washout) : Some mineral patches in hybrid bases can be destroyed by cooling towers.

Miscellaneous

On Exarch, worker-only paths allow workers to travel about 1.5 seconds faster than the 31-second ground rush distance in close spawns. On other maps, workers use the same shortest path as other ground units when traveling ramp-to-ramp.
On Rorschach, the healing shrine is surrounded by air blockers. However, on Voidstorm, it can heal air units.
On Old Sun Temple, spawning at Top-Left (TL) or Bottom-Right (BR) differs from spawning at Top-Right (TR) or Bottom-Left (BL) due to rotational symmetry and the absence of vertical spawns. In effect, there are 2 variations of the same map: Old Sun Temple TL/BR and Old Sun Temple TR/BL. For example, the TL/BR variation allows Zerg to take the linear 3rd blindly because the enemy base is never close to it whereas TR/BL variation may place it right next to the enemy base. Therefore, at the start of the game, players can identify which variation they are playing based on their own spawn location and adjust accordingly. Note that player 1 may be playing the TL/BR variation while player 2 experiences the other TR/BL variation.
For reference, the "Map Size / Fear and Faith" values of Mothership (current largest map) and 10000 Feet (current smallest map) are 84 and 68, respectively.
The number of features or lack thereof DOES NOT indicate map quality. Factors like base layout and openness/narrowness are often more important, though they are difficult to quantify and tabulate.
Ladder versions may differ from TLMC versions. Mapmakers often make adjustments based on feedback before ladder release.
This is independent research, and I have tried to remain as objective as possible. I am not affiliated with the TLMC organizers or mapmakers of these maps. I do not intend to endorse or criticize any specific map.

u/Guinpenza

Note

Miscellaneous

Link