A: Client window launch sizing... by default it is a full window that cannot be resized. Using the button to shrink it, not minimize, defaults it to 1080x720 or somesuch. It can then be resized, but the result is a complete hash of your UI window positioning.
Have the client remember the last window size state and resume it on launch.
B: A directional pointer on the map window, or change the diamond to a triangular shape more indicative of facing.
C: A contract system for transferring goods at a distance. (perhaps in some distant future iteration).
D: Remove the 'primary target' requirement. Make the topmost target 'default' if none is manually selected. Place a forward arc on the ground in line with the mech's facing so secondary targets within that arc can be fired upon. If the secondary targets leave that arc the weapon discontinues firing, or switches back to the primary focus. The arc would probably be limited to 135 degrees.
E: A range indicator for weapons. An indicator on the mech status display that shows maximum lock range (the white 'ring' around mechs does not seem to be highly accurate).
F: Limit the number of E-war mechs in mobs. 6 E-war spamming mechs is a no-win situation much of the time. Make player E-war as effective on NPCs as it is on other players (ECM currently has little effect because NPCs lock nearly instantly).
G: The ability to 'pin' windows in place so that resizing (as mentioned in A:) does not scatter them all over the place.
H: Ore quantity indicator, or cycles remaining as plants show. This can be problematic with liquid type ores, however.
I: Pathing needs to be re-examined. Mechs on autorun should adjust to obstacles in their path long before actually getting stuck against them. Add a mappable 'autorun' key... call it "Cruise Control".
J: The ability to see what you just sold rather than just the mystery income from a sale. With a lot of active market orders this can get hella confusing to see what's selling and what is not.
K: In the sell item window put a 'examine market details' button to make reviewing market on the item in question a lot easier.