I think 4 more LD maps would be cool to add with the following themes:

1) LIBRARY (3 point)

Basically this map would be relatively dark, with blue sporadically placed candles to light the way. The map could have a single Grimalkin stalking around, and each point could have an orange candle in the middle, which could be lit with the fire ball pickup to fend off the Grimalkin while capping.

The Grimalkin thing might be too much, but the Candlestick Keep levels are some of my favorite levels in terms of music and design (really like the haunted mansion theme), and it would be awesome to see a lockdown level designed around the Candlestick Keep theme. Maybe we could get that Candlestick Keep music in the lockdown level as well?

2) MANSION (5 point)

Same as above, but 5 point (and maybe have more orange candles along the way that could be lit by the players) -> lighting candles may change the fighting dynamic, it would be cool to see if people light the candles or if they keep them off to fight.

3) SUBTERRANEAN (3 point)

Lichenous lair/Slumber levels are like dream levels (especially with those stars in the background), and it would be cool to have a lockdown map based around this theme. I am thinking 3 point map, with glowing (non-attackable) minerals lighting the pathways to enhance the subterranean theme, and other stalagmite type structures jutting from the ground. Also, there would be periodic falling stalactite cones that could damage players on the points (like the tortodrone guns kind of -> randomly throughout the match, there would be the warning circles appearing on a point, and then the stalactites would fall and behave like the tortodrone gun charge. This would be an interesting map for bombers to adapt to. The stalactites would fall every....say, 30 seconds, not too frequently)

4) PALACE (3 or 5 point map)

This map would be based on the new treasure vault levels. The outer boundaries of the map and all boundaries would be designed with that gorgeous gold trim from the treasure vault levels. The floor would be checkerboard pattern, with normal tiles mixed with gold plated tiles. Basically lots of gold and crystal type designed throughout the map, with gold piles or treasure boxes outside of the boundaries as decorations (in an unhittable location).

Currently, we have a nice selection of 16 LD maps:

Freeze themed:
Avenue
Downtown
Frostbite
Icebox

Poison themed:
Pipeline

Forest themed:
Forest
Necropolis

Fire themed:
Furnace
Fortress
Ramparts
Stadium

Mecha themed:
Mines
Reactor
Facility

Grass themed:
Gardens
Ruins

4 More could be cool to get it to a nice, even 20