yes, i know wings are coming soon. would love some more insight as to "when" ... i know slave fsd is off the table because it's apparently too difficult to program it. ... worst excuse i've ever heard btw.
other co-op stuff would also be lovely (dungeon style stuff perhaps, other objectives, etc.).
unfortunately the best you'll get on "when" is "soon"

however given the rate of progress of ED first half of 2015 seems very probable.
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The dropping of "drive slaving" was done primarily because the dev team wanted to move in another direction. Rather than make the pilots of the "slaved" ship passive passengers whilst being directed by the leader of the group, FD wanted a more hands on "flying" experience with group members having to communicate and the effectiveness of the group being down to the piloting skill of the group.
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To do that they are aiming to make communicating between members easier (possibly group chat, possibly shared targets) , seeing where members are easier (colours on hud?), seeing the status of other members easier (under attack, charging, shield down) and finally making following members from SC into instances easier.
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When i first saw that FD were dropping "drive slaving" i was disappointed, but after following the thread where FD laid out the decisions and reasons i came rpund and am looking forward to their new interpretation.