I believe that most of the main modders may have moved on to other projects. Stant, who would have done a lot of the work, doesnt use steam. The last mod update was out a week when the main game updated and heartbreakingly mussed things up. My biggest fear is this mod is going to die a slow death. Also, they have lives outside of distant stars and have to use their time wisely. Maybe its time for a donate button button. Money can be a motivator. I would gladly donate. 

What exactly needs to be done in order to update the mod?

Is it just balancing issues because of what got changed in the 1.1 patch?

Heh, basically, you got my sometimes barely working port over from diplomacy plus changes to make it work more often then not, and the new ships added in.  There are no balancing changes done to it, some of the new tech is missing, and pretty much everyone is busy working, having lives, and raising families.  I'm only doing one of the three, but working as many hours as I do would prevent me from doing very much even if I didn't have a huge dislike of Steam.

So to answer the question:

• Go over each faction, every single research, ship, structure and anything else of concern and add in anything that is still missing.
• Review and adjust the values of the research items according to the general standard presented in that tree, as well as putting each item in it's proper place on the tree.  Also new techs may be added, or in some cases, techs get changed from one faction to another in order to further separate each faction from their counterpart, meaning the Advent that want to keep fighting should maybe get better hull upgrades then their peaceful other half, but their peaceful other half should maybe get some eco boosting stuff courtesy of their Trade Order friends.  You know, things that keep in spirit with the purpose of the faction, yet don't make everyone say this faction is now ubered up and we only will play this one from now on.  In DS, we want clear sides, but we also want checks and balances so that it's basically one big game of rock, paper, scissor, lizard, mr spock.
• Review every ship, especially the new ones.  Most will not need speed/turning/hull/shield/firing rate/damage/etc adjustments, but those that do have to not only stand up to DS levels, but also fulfill it's role more precisely.  What does that mean?  It means in the case of the Marza for example, it's supposed to be a ship killer.  In plain Sins it does this "A'ight" to borrow from the urban vernacular.  In DS, it eats frigates for breakfast then invites cruisers over for dinner and makes them it's bitch after a little sweet love making of course.  Now in Rebellion DS, you've got that second level of Missile Barrage.  It should handle other capital ships like they're little red headed bastard step children.  And by that I mean smack them around and make them wish they never left the ship yards.  In keeping with that, the new ships need to be battle hardened like other DS models, and all ships need to be evaluated to make sure that the new ships fit in to their roles nicely without the other ships stepping in on their territory.  This might mean that some things need to be taken away from another ship just so the new one has it's purpose and get's used for it, and the ships that lost stuff, either get new stuff, repurposed to do a different job, or just powered up or less costly to finances or fleet supply to make up for it.
• Review every single structure.  Make sure the DS counterpart has the stuff the unmodded version has, and then like the ships, make sure it still serves it's purpose without infringing on another structure's purpose.  Bring it up to DS levels of usefulness and vitality, and by that, I mean whatever got added in needs to function like it was created for DS and last the appropriate amount of time that makes it useful enough for a player to want to use it, but costly enough to make then have to think about using it, not just do it as a matter of fact simply because it's there.  In some cases, it's function may have to be changed from user selected to always active or vice versa.
• Balance and testing.  This is the most important and the most time consuming portion of updating the mod to a different expansion.  If something is overpowered or underpowered, the only way to know is to play a game six times over.  The faction being tested against itself and the other five.  People play different ways.  Some play aggressively, others play defensively, some use better strategy and lure you into ambushes, traps and other methods of gang banging their way to the top, others play with no strategy at all and throw whatever they got at you, and others do absolutely nothing at all until you get tired of waiting and go in their and beat them into oblivion.  So six test games turn into 30 test games real quick, and Sins can take up hours for just one game.  And that's just to find out if you need to change something.  Once you change something, you have to start all over again.  This is why feedback from the general public is not only immensely helpful, but kind of critical.  Me playing for 200 hours just to check one change means you don't get updates.  You all playing for 20 minutes and leaving reports as if you were a team member means I only have to play for 20 minutes myself to evaluate what effect the change has on everything, which then translates into advice being passed on up the chain for official approval/denial which means updates are made much more quickly.
• Bugs.  These things happen.  So do typos.  Like the balance and testing, considerable hours of game time need to be put in to not only find them, but make changes if even possible, and then put in considerable more hours to make sure you at least lessened the problem and didn't create any new ones, preferably eliminated the issue, and squashed a secondary one at the same time.  The hardest part about this one is when something happens off screen or is part of the pirate research or something that just kind of happens for no reason some games but not every game.  Like the trade ports in the neutral grav wells in Diplomacy.  Some people crashed every time those were in the game.  Me personally, didn't crash at all because of them.  The tendency of the game to crash for most people was traced back to them, so they were removed even though people generally liked having them.  This is Distant Stars, not Place Where Miracles Happen.

And that's just for the factions.  You still have things like the galaxy scenario definitions file to go over, the different sound and graphics things, meshes, the various string files, planets, bonuses, artifacts, pacts, and anything else that happens behind the scenes...  Everything has to be looked at several times over from as many different perspectives as possible just so you can make sure you got everything.

Once all of that is completed, then sent on up to Nacey and he's had time to mess around with it, and he's had time to pass the changes along to everyone on the team for internal review, and the team has had time to give their input, then, and only then, will the update for Rebellion be released for public review.  This isn't a simple, Rebellion 1.1 to 1.11 update patch, it's a massive Diplomacy 1.32 to Rebellion 1.(whatever you guys are at) upgrade that doesn't have the support of everyone that Diplomacy had, nor the hours to be given to it from those that do support it.  So it's gonna take some time, and if you're like me, then you're going to just do the things I outlined above on your own version and just keep sending things to Ryat to make him deal with it and pass them along and eventually, someone out there will have done everything that needs to be done, it will have all been passed along to the powers that be and you'll earn a spot on the team and take your rightful place in front of the firing line when people want to bitch at you because your update wasn't available 10 minutes after a patch was released on steam. 

And to add to what Stant has said...

Besides real life with family an work, we all have other things to we like to do in our free time. Other Video games, TV to watch, books to read, blah blah blah blah

There was a point where all of us play this game often and alot (i.e. Diplomacy era) so it natually got more attention and got modded more often. Hence the slowness of any update is simply modding has taken a lower priority to other ways to spend our free time.

Oh, and as its always been everyone is on a different time zone so add jet lag to the list of things slowing down updates.

If it bugs you that bad that there not one, now is a great chance to step up and learn some modding. Everyone on this team so far has done just that at one point.

Not currently no. Some of the bugs are very difficult to track down.

I can play the mod without crashes and errors since the superweapons were disabled. Already played 10h or more without crashes.

Remove them from the GalScenarioDef file, remove them from the player files, remove them from the entity list...  Adjust the counts accordingly.  Each will do the job, doing all will do the job better as it won't cause other errors to creep up.

Goafan has a good one as well.

Yeah, mod friendly for tweaking really.... but for my own badass models and effects? No, not simple at all.  I tried a long time ago, and just got frustrated and gave it up.

http://www.moddb.com/mods/crazy

That isn't a bad mod.  It is that guy's take on what Distant Stars has done, and with extra craziness added in.  It will work as a good substitute until the DS team releases a more complete Rebellion version.