Small maps have several downsides:
1. not many places to go - people go to the same places every match and gameplay is very stale. Example: Frozen City, Viridian Bog, Canyon Network, Caustic Valley, old River City, old Forest Colony, and to an extent HPG Manifold
2. teams meet each very other early in the match, so areas of engagement are heavily dictated by the spawns and there is no time for the teams to deviate and engage from different unique locations
3. scouts (and really all lights mechs) are marginalised. Speed isn't as important and since the map is small you'll always know where the enemy is, so light mechs are relegated to the same duties as mediums and heavies, which is simply laying down firepower.
4. not much space means that weapons like the AC/2 are going to continue to be useless and weapons like the ERLL and ERPPC won't be viable (notice how ERLL spam is prevalent in CW and competitive matches, but never in group or solo queue). Maps like Mining Collective, Viridian Bog, Caustic Valley, Canyon Network, Frozen City, HPG Manifold... don't offer any sightlines long enough for long range weapons to be valid.
So what's the problem with large maps? When they break any of the above rules.
New Forest Colony - it's huge, but rules number 1 and 3 above: not many places to go, the enemy will always be in one of two locations and lights have no role to fulfill. So you end up walking forward toward the enemy several minutes and engage in the same locations every match. This is because there are so many large obstructions and out-of-bounds areas cluttering the map and funneling teams straight into each others. These massive obstructions need to be removed (the mountains) and the map needs to be opened up so that more avenues can be explored.
New River City - it's somewhat large, but rule number 1 - since there is a river running down the middle of the map, there aren't very many options. You either fight over the bridge/park area, or the citadel. The rest of the map is completely underutilised and a complete waste because there's not enough avenues to make use of that area except for weird stuff that happens in competitive matches. (hint PGI: open up the north end above the dam, the ten grids squares from B2 to C6 and suddenly we'd have more options on this map)
Crimson Straight - it's a decently large map, but only two avenues: saddle and not-saddle. Everything in group and solo queue basically revolves around controlling the general area surrounding D4. Rarely do you see matches deviate from that because that's the place where teams meet if they just press W from spawn - there's no meaningful alternatives.
Caustic Valley - it's okay-sized,
but fighting only happens at the caldera! Only nine out of the whole
thirty-two in-bounds grids on the map are ever visited! 72% of the map is completely wasted! Because there is a nascar feature in the middle.
Terra Therma - lovely large map! Spawns are far away, gives teams plenty of time to diverge and meet in different locations and have exciting battles all over the map, scouts are important because you can't see where the enemy team is headed without them. But wait. Actually, everything I just said is a complete lie because the center of the map is dominated by a caldera that everybody auto-pilots toward every single match. That centrally-placed caldera ruins EVERYTHING. No point in scouting ... you know where the enemy is going to be every single match - the caldera. No need to plan anything out tactically, there is a default strategy every match - go to the caldera and be better at it than the enemy. We use four grids on this map out of the forty-nine(!!!!!) that are available. 92%(!!!) is completely wasted because there is a central features that draws everybody toward it.
Alpine Peaks - another lovely large map! Spawns are decently far, so teams have plenty of time to adjust and go to new locations and engagements could happen at any location on the map. Except they don't... because just like Terra Therma there is a dominating feature on Alpine Peaks - the I9 hill which draws EVERYBODY toward it. Going anywhere else is useless because I9 hill is the stronghold that can control the rest of the map. The fighting only occurs in six grids regularly, the other one-hundred-and-one (!!!!!!!!!!!!!) grid squares are completely useless ... well except for the seven other grids that are fought on during Conquest, so let's go ahead and include those. 13/101 means 87% of the map is going almost completely unused. The main fight only ever happens in 13% of all space on the map. A complete waste... all because of a central dominating feature.
Polar Highlands - amazing large! Long sightlines, but ample cover throughout the rolling hills to break the sightlines everywhere. Spawns are very far away so teams have time to diverse and meet each other in vastly different locations every match. Scouts are actually important! Without them you'd have a hard time actually finding the enemy, and once you do find the enemy, having the lights flank them is that much more valuable because of how large the map is and how you can come from unsuspecting angles or create brutal crossfires. AND THERE'S NO DOMINATING CENTRAL FEATURES, E-GADS IT'S AMAZING! I've seen main engagements that can occur in any of thirty-two(!) different grids. That is a LOT of variety. About 66% of the map goes somewhat unused, but holy crap 32 grids worth of places to fight over? That's amazing and that's what this game needs more of. Flippin' VARIETY.
Edited by Tarogato, 09 February 2016 - 10:13 PM.