The project is alive, no question about it, and something should happen but, like I said, I have no control over what or when. Don't forget that MM develops these things for his own amusement and could just as easily decide to keep it to himself (he's said that more than once, and he has several sceneries unreleased, Nairobi, Cairo, Luxembourg, Rotterdam, Ostend, Lokichoggio and Bole, that he does tiny bits of work on as he discovers something new about the airports). Its just his personal amusement that he doesn't do for anything other than pleasure, no deadlines, no expectations and definitely no demands.
AUH got complicated because there was a flood of information from someone who visits the airport often, and it was worth taking it further. Without that information it would have been released freeware a year ago and be inaccurate (especially by now). Even though I have a copy, if he asked me 10 Euros for it tomorrow I'd pay up simply because I get more than that in pleasure from using it, same as I do for Martin's more complex and detailed sceneries.
I'm also not going to get into a discussion about what people want and what they'll pay for, mainly because that decision is nothing to do with me and so are the "ethics".
@biloo - the T1 building is massively changed from your model. To increase the space inside the building they added lots of ugly stuff around it.There's also a new external walkway around the front of T1's arc building and the windows set back at the top are all flush-glazed by now. There's also a sub-terminal (T1A) built in the service vehicle layer at the base of the terminal. And that's not even the new part of the airport! The base of at least one of the small satellites is also now boarded/glazed making its pedestal a lot "fatter". If you decide to carry on with AUH in the future, it might also be an idea to use a satellite picture of T1 in your Gmax viewport to get the proportions of the terminal absolutely correct. I had a long discussion with MM last year about T1 (because I saw some proportions I didn't think were right) and he changed a couple of aspects that threw everything else into disarray. I was not his favourite person for a while! Its one of those buildings that, once you start adding the jetways (and every one is different - they come out of the building and to the plane at different angles (and lengths, and heights - some are just for narrowbodies), the docking system has a different heading and stop distance on every gate, its a nightmare changing just one small thing, sometimes. Making those little satellite "pods" larger could, for example, mean changing just about everything. There's also a discussion at the real AUH about bringing the 2 disused gates back into operation (the ones nearest to the arc terminal) for small regional aircraft.
Also with the shape of all the T1 buildings it is critical to remove unseen faces and make at least 2 LODs for the buildings because they are quite complex shapes if accurately modelled, and if they are visible at 10 miles that can really hurt the frame rates. At the present version of AUH I'm using, the frames are now about 19-30, but only because so much optimisation has been done and LODs are used extensively (of course that's all completely meaningless because there's no ground picture).
Also, as I said a short time ago here, its not at a point where people can join the effort because none of the things that need doing are large enough to make it worthwhile. It takes more effort for MM organising and perfecting a small thing made by someone else, than making it himself. If the idea was "make terminal 3", that would be enough to keep someone very busy, but if its "change the number of lights on this lighting pole and make it bi-directional - that can take 10 minutes of cloning, saving and exporting, far less than it would take to give the task to someone else and co-ordinate it - and that's where the scenery is at.
Of course if he was to make ground images, that would be a few more months, I guess. Still, that's what you have to do if you want to please everybody

.
I'd personally advise him to release a version with just T1 and T3 and downgrade the rest of the scenery to using default objects again, reserving the more detailed version for people who are prepared to recognise the time he put into it, with a small payment.