I bought the CMO/Tacview package on Steam and used Tacview for about a week and realized it added very little of value for me. This was not an effect of any fault that I could find with implementation of Tacview in CMO, it's just that CMO, as a fundamental concept, is a game that was not primarily meant to be experienced from the eyes of a fighter pilot or something like that (This is in no way meant to imply that I fault the developers of CMO for making Tacview an option - I perfectly understand the reasons the developers had for making this decision).
I understand the longing for Tacview as fundamentally coming from the drive for ever nicer graphics in games. The drive for ever better graphics is a long--held mainstream opinion among gamers which i can't say I disagree with in general (Note that this being mainstream is not at all meant to belittle the people who hold those views).
The concept of CMO is on the other hand not a game at all focused on ever nicer-looking graphics: It is an operational level (Primary air/naval) battle simulator with a focus on realistic simulation while maintaining playability and with almost zero focus on a fancy graphical representation.
So this conflict the CMO community has here is in my opinion a clash between two different computer game traditions: The more mainstream minded players's quest for nicer-looking graphical representation and the typical war-sim player's valuing realism.
When I play CMANO i don't use any sound, very seldom any music, I use NATO symbols for units and sometimes turns the lights down a bit to get the feeling I am sitting in Cheyenne Mountain in 1984 so I am squarely one of the people looking for simulation realism while maintaining playability with graphics, sound effects and music being of very little use. That is the type of immersion suitable for this game for me.
The thing that most would heighten immersion for me, except a more realistic and playable game, is implementing some way more advanced version of SeaHag that would heighten the feeling for being an OiC of an operation surrounded by your staff in a command facility by having people talk to you frequently).
I though understand if most new players would expect there to be fog of war in Tacview when they bought CMO since it is a pretty universal feature across games and that lack of FoW can be very irritating.
On the other hand the developers could hardly have done more to inform potential buyers about Tacview lacking Fog of War. In the material that was released they were very clear that Tacview was a separate product that was sold as is and FoW is not a feature of Tacview. And besides, refunds were possible.
Now, to solutions. I have no insight into how hard it would be implement FoW in Tacview (But I guess that for instance how to represent units detected as being somewhere within an area of 3x3 nm that's constantly changing will be very hard to give a fair representation in Tacview space that is not just confusing and irritating with units jumping around on the screen from second to second without makinga a substantial development effort) but I realize this would probably increase sales in the long run, potentially leading to a better outcome for all interested parties, besides making those who value Fow in Tacview happy.
If implementing FoW is a medium to hard, quite time consuming project, it might be better to include the functionality in a Chains of War style-update to make it a selling point for a product to bring in further revenue for development of the game.
It's not like those of us that are more of the typical purely realism-minded war-sim types have not waited for our favorite and quite fundamentally game-changing functionality to be added for very long times (For me that is the Advanced Strike Planner or Weather fronts plus now in CMO, when it seems to be a possibility, complete editability of units).
I just wanted to give a different perspective on this topic that I have not seen represented in a single unified post in the thread, from mostly the other side of the issue while still considering the at least in parts valid critique of lack of FoW.