Honestly, I agree that the rumors of 6E are mostly people who have tried 5e and found it spectacularly wanting. Part of the clamor is because there are enough areas of the game with enough structural problems (read: Matrix) that it is simply impossible to imagine how they could fix things without major revisions or, in some cases (read: TMs), a complete ground-up rewrite. Combined with the... anemic modification rules for vehicles, drones, and weapons, a return of the priority system, and a failure to follow through on their own hype (remember the 'Year of Shadowrun'?), this has left a lot of people disaffected with the current edition. The CFD 'crisis', which was built up so much leading into 5E has turned out to be thoroughly 'meh', and the Lockdown relied too much on the computer games which never caught on, and we were left with... well, a bunch of nothing for long enough that the only reason people were talking about it is because it screwed up traffic on the eastern seaboard, until very recently, when it was almost an aside with the corporate court looking at NeoNET and the Audit. Even a shakeup in the corporate court and the megacorporate landscape was given a ho-hum treatment. It is basically like Shadowrun has been running on neutral for the last few years.
There just isn't the same energy in the lore in 5e as there was in 4e, and the structural problems 5e has are much more pronounced over those 4e had. At this point I think what is needed is either an overhaul, like D&D 3.0 to 3.5, or a completely new edition, like D&D 4th to D&D 5th.