Hi, all. Some suggestions for 1.1 or expansion consideration. I think all of these are within the "spirit" of Sins canon and warfare, although others might disagree.
A number of people desire better planetary defenses, particularly in early game. One thought for this is a turret that autospawns up to five armored drones that it controls (much like a carrier builds up to a certain number of fighters). These drones normally park beside the turret, but when an enemy fleet arrives, home in on attacking forces and hit them with a relatively weak area-effect self-destruction EMP-like explosion that primarily shorts out shields (thus making it of limited use against pirates). Five successful close detonations would be bad news for a massed shielded fleet. This would be particularly powerful against frigate spam, and could cover the entire grid within its range, although travel time for the drones would be a consequence of building it safely far away from the attack vectors (i.e. at the other side of the gravwell from the phase lanes). The unit could build one new drone every 30 seconds or so, replenishing its supply as soon as the number of drones it controls falls below five. Attacking drones could be taken out with mass focus-fire, and the structure would have a switch that the player could select to allow or deny its ability to fire on enemy scouts. Gameplay advantages: very early build menu defense; effective against player or AI frigate-spam; ineffective against multiple-attack-vector assaults (which is desirable); counters the missile-frigate-spam-at-edge-of-gravwell attack. Gameplay disadvantages: might promote the use of micromanagement where attacking players position their fleets before warp-in to hit at various points on the target gravwell.
One thought for planetary defense that might be more mid-game is a mechanism to affect transit speed in phase lanes themselves. This 'tech could slow down vessels approaching the planet in phase space to a fraction of their normal speed once they pass the "halfway point" in the phase lane. This Phase Lane Disruption structure will allow the player time to better organize their own fleet for defense, and might be upgradable to increase its efficiency (e.g. level 1 = slow approaching enemy to 50% of speed; level 2 = slow approaching enemy to 25% of speed). It would require the "detect hostile forces" technology as a prerequisite build item, and any phase lanes that terminate within a specific radius of the structure's construction point would be affected. Advantage to gameplay: encourages good defensive planning strategy; a "passive" defense that only assists the player with time to organize their own defense and does nothing to help defend planets that are too far away. Disadvantages to gameplay: slows down gameplay by partly trapping enemy fleet; could encourage more stalemates at heavy chokepoint battles.
Finally, an anti-siege frigate spam defense might be a planetary gun. This automated low-orbit planetary surface building would use up a 'tech spot and rapidly traverse the equator to automatically fire only at any sieging craft as long as planetary health > 0. Advantages to gameplay: siege frigate spam would be more costly to attackers; requires no interaction from defenders once built; a unique 'last line of defense' option. Disadvantage to gameplay: might encourage attacking players to micromanage siege frigates by swapping them in and out to avoid having them destroyed; may increase balance of power toward capital ships.