I'll post few features here up for discussion. I feel that these features support each others to some extent so I'll try to focus them in the same place. I haven't gone through all the feature topics (almost none tbh) so sorry if re-posted ideas.

Feature 1: Mines

I suggest that in order to create more tactical in depth especially for PvP but also for PvE we would introduce land mines. Mines could serve few different purposes that I can think top of my head. They could disable/slow down movement for certain period of time or inflict damage either in area-of-effect (fragment mine) or heavy single target damage (heavy armor mine).

For this feature we could introduce few skills where agents could specialize. Following skills come to my mind.

Skill: Mine deployment
Each level in the skill adds 1 to maximum deployable mines.

Skill: Mine concealing
Each level decreases mine visibility by 1.

Anti-skills:

Skill: Minesweeping
Level 1 enables use of T1 mine sweeper modules
Level 3 enables use of T2 mine sweeper modules
Level 5 enables use of T3 mine sweeper modules
Level 8 enables use of T4 mine sweeper modules

Skill :Mine detection
Each level adds to 1 to detection of mines

Modules

Mine deployment module : Enables deployment of mines. Each tier adds 10% to mine concealing.
Mine scanner module (passive): Each tier adds 10% to detection of mines
Minesweeper module (or could introduce even robots specialized for mine sweeping): Each level reduces 10% time required for deactivating mine.