Love the idea and the concepts. A map idea for you. an office building. A 4 floor 4 building complex with long sky walks connecting the 4 buildings on the top 3 floors in a square shape footprint. Perhaps with parts of its roof on fire. One team spans at the top, and has to get to the bottom ( or kill all other team) the second team starts at the bottom and has to get to the top ( or kill all other team). The open area building floors will also have some smaller offices as well, allowing for a range of combat style and weapons. The long 'glass' sky walks are perfect for effective troop movement, but also perfect for snipers.
You can incorporate repelling from the fire escapes, all the room clearing tactics would be key, hide and seek, could be very intense, anti personal devices like proximity sensors and motion tracking assets the users can place around.