I think this is a story that has happened to a good number of folks. Peeps showed up excited by the concept of the new edition, and then had come apart with more regular use.
To me the way forward is simply revise your games back to your preferred previous edition.
To me 3rd or 4th are our most complete editions. We have everything that came out for them, and we can easily build complete and complex campaigns with those completed rules sets.
If folks are unhappy with the current writing then go back to before they took over. It's a simple and straight forward solution to the problem.
Ideally yes. Current editions have a certain power though. The missions for example will be designed for them, so people who do those are kind of stuck. When I run things I mainly use published materials, but I'm okay using a 6e mission and turning it into a 3e run. Its some work, but less than building one from scratch and I'm just too damn tired to make my own adventure from scratch every week. I wonder how many current 6e players are playing it not because it is their favorite edition but just because it is the current one. I guess a similar question on the other side would be how many players playing older editions never gave the current one a shot, or just aren't playing it because not enough material has been created for it yet.
See, for me, I have never really used any of the published adventures 
Yes, I have them and have read them, but they are never a good fit to the group that players have created for various reasons. So, I have often had to rely on creating my own adventures, some times right on the fly, for my table. And after years of doing so, I have gotten pretty good at it..
So, for me and GMs like me, The Edition changes that happen are more or less just a chance to try something new, and see if we like and enjoy the new meta...
Often times, we stick to the new material just for ease... But if something really upsets us, we can just revert back to an older edition and continue on. And for Shadowrun, where the plot is mostly meta, the rules under which the "world plot" advances doesn't matter... IF "world plot" even matters to your table....
Plot often is the first casualty of contact with Players..
If I had the energy I'd make my own. I have a sleep disorder and most nights watching TV takes too much energy.
If it helps, i generally take notes for adventures all through out the day, be tgat something at work, in the news, in a book, etc.
Then, during lunch breaks, I go through the ideas and discard any that I can't work the whole team into, in less then 30 seconds. (This usually gets me down to 2 or 3 ideas).
Next I develop the ideas over the next few days into 'rough runs'. Nothing fancy, just the goals, number of puzzles/encounters I expect.
From there, its just 'fill in the blanks'...
Mind you, this style works best right out of the gate with a fresh party. That way you can datamine adventure ideas from the best source first - the Player's Characters.
Players usually always have some back story for their characters. Most of it is unusable, fanfic nonsense.... but there are some gems in thete that can be mined.... like that high loyalty contact, or even just the name in that high quality Fake SIN a player has.... with enough imagination, and boredom, just about anything a player writes down can be an effective hook that leads to a whole rabbit hole of adventures.....
Trust me.... a little imagination, a little effort, and a little creativity: yiu got yourself YEARS of game time from the same characters....
I posted a few "drop in" runs for GMs in the GM section a couple of yeats ago now (Seras has expanded on them). They are worth a look to see what I mean. None of those took me more then an hour to set up, or if you need help, hit me up.
