This thread is kind of out of date so it is time to post a short overview of what has been done and I was encouraged to post a new update here.
-11 new systems
Badlands is what we are proud of. As always you can customize all systems via configuration options. So Badlands vortex's can be tailored to own taste i.e.
-New Campaign 
10 instead of 5 missions like in the first campaign (v3.0 campaign), so that's 10 more missions
-New mini missions 
I aim to go over 30 mini missions, since they are very easy to do. So that should be +40 missions in total
People said there were too few missions in v3.0, so we listened.
-Entering wormhole manually
People wanted to fly into the wormhole, so we listened. Don't worry you can still press the button for the auto sequence to take you in.
-Easter Eggs
Some are meant for fun but some actually will unlock new content ;) what that is, you will find out when it comes out...
-Fixed fully to work like it should
v3.0 issues are no more, the core has not been rewritten but totally redesigned to fix all the issues v3.0 had.
-Sets have custom music
Music is not static anymore (to be more precise one music piece won't be replayed over and over again, unless you want it to). When you enter a system it is mixed and when battling custom battle music starts. Minor detail worth mentioning. Although including the music in not a option nowadays.
-Life Support
Something I haven't mentioned much before but what is it... And old idea which was planned to be developed for Immersion. Generally it has been toned down and adapted for DS9FX. Ships have crews generally which can be defined in the ships plugin (BCUT already has the feature support). 
So is it just for show or it does something?
Ship which has 80% of crew capacity won't be as nearly as effective as ship with 100% crew capacity. In combat this effect can be seen and noticed.
If you kill the life support system on a ship (if it has one) the ship is dead in water.
Ships can be taken over by transporting teams to fight for control over target ship. Ships with no crew can be salvaged, this is particularly useful in some missions which you will undertake. Not just in missions, using it with GC 2.0's war simulator can be most amusing.
I believe somebody will ask this, so I will tell this right away: Yes docking to a starbase will replenish any ships crew and yes crew does die in combat also.
- No Damage Through Shields
Actually developed for Life Support this, if enabled, will simply prevent any damage from going through shields if they are operational. Something that I noticed bugs most people. This does make battles more interesting.
-All about customization options
I don't think I need to talk about this, but anything which is featured in DS9FX can be customized.
-Minor touches to the systems
These are aesthetic options but seemed like they add more depth to the mod and overall experience. Every planet, every system can be scanned which will provide some background information about the system or planet.
-Automatic backup/restoration of Mutators
Some people experience mutator "deactivation". This, if enabled, will simply keep track of all enabled mutators and restore them when needed automatically so you will never experience such a thing ever again. Minor detail worth mentioning.
These are some of more noticeable features, but there are a lot more.
It is difficult to summarize all the work done so far.