Yes, they have to show off before release. It is required for marketing. All DCS modules have at least 6-12 months of preview screenshots before a release date. The F5 was shown off several times, and so were all other modules. However we did not get not even one screenshot of the Viggen.
Also for me it looks like a clear confirmation that the f14 won't be out until december 2018. Proof is the AIM 54 developer update. Not one single word about the release date or actual screenshots of the cockpit. When a developer update completely dodges the most important question, which is "when is it out" then that is a clear indication of massive delays.
It will take at least 8 months after the first screenshot of the Viggen for a release date even to be mentioned. Also they have to stay away from other module release dates, becaus I think ED does not want module releases close to each other so the sales do not interfere.
The only thing that will be on time this year will be the spitfire (my guess second week of december) and the black sea and nevada maps unified in the same game.
I have not the slightest doubt the LN modules will be great. But their release date estimates are phenomenally bad. And to be direct, it was sort of rude to drag us along with "3 modules around the corner in 2015". Was really frustrating to follow news releases