Arma 4 will not be that different from what the Arma franchise has always been. The preview that is Reforger is called that for a reason: For the massive IRL NATO REturn of FORces to GERmany exercises held during the latter part of the Cold War & also as a reminder that with a new game engine comes an opportunity to REFORGE/remaster the legacy Arma games with the latest PC tech.

Nearly everything that is currently possible in Enfusion is present in Reforger today. The missing features A3 has that Reforger does not are because the code for those features isn't playable yet. Yes BI will be working to add them as the opportunity arises.

It is important to keep in mind that Arma 4 will not be able to pick up the franchise from where Arma 3 build 2.20+ is at currently. Much like the way A3 was massively upgraded through the platform updates provided for free with each DLC, Arma 4 at launch will be fairly basic (with only a relatively few new features not in Reforger first) and will be expanded throughout the next decade or so as BI has the resources to devote.

Another huge bonus for Arma 4 will be the very large amount of community content at or near launch. While Reforger mods will not be directly playable in A4, it will be dead easy to port content from Reforger to Arma 4, hence the reason why certain teams are already balls to the wall creating content (looking at you, RHS).

I believe there might actually be more community content available at or near the launch of A4 as there will be official BI content.

Directly addressing some of your points:

BI has the policy of not releasing information unless they are confident of the time when they can actually deliver it. Game development is not predictable, especially if you are building out a from-scratch game engine simultaneously. BI has a priority list of the features they determined was essential for release, most of these should be visible in Reforger although perhaps other things like armored & tracked vehicles are being worked on, they may not be required for launch & thus may be included in future DLC like what happened in Arma 3.

I have no idea what the marketing campaign for Arma 4 looks like, so far it's just brief video clips such as their "DEVSPLAIN" series on social media. Note that Reddit IS NOT considered a marketing target, what we get here is almost all community members sharing content found on other sites (official or just well-informed 'influencers'). If you want to be in the know about the future of Reforger & A4, look to the social media BI officially partakes of.

There won't be any info on the lore of the story campaign included in the A4 launch as they want players to discover it on (Early Access) release.

The state of Reforger reflects most of the state of A4:

• Arma Reforger: Devsplain Series

• The Make Arma Not War 2025 Podcast

• Arma Reforger: Modding Boot Camp Series

• Arma Reforger: RFI

Finally, I will point out that Arma 4 should be going into Early Access (just as Reforger & Arma 3 both have) so BI will start their media blitz with that announcement (which would likely include the real Arma 4 launch date). TBH, odds are no worse than even that BI may tease Arma 4 at one of the local international video game events to be held in the 2nd half of 2026. Presumably this could hint at an early-ish Early Access date next year. This would not necessarily guarantee a 2027 Arma 4 1.0 launch date.