Personally for me, its all about the aeroplane FMs.
As an engineer with a firm understanding of aerodynamics, engines, and advancements from this period, I have a tendency to evaluate each individual aircraft on its own merits.
If a Nieuport 24 can outturn or equal a Fokker DrI, you immediately have simulation problems.
Modeling flight characteristics of individual aeroplanes in conjunction with damage modeling is a tough nut to crack.
Not only do you need to understand the limitations of the era, but fundamentals in physics as well.
Thats why it was so sad to see MicroSoft's flight sim crew be disbanded.
Artists and modellers can do the graphics, but they cannot model the flight effectively.
OFF provides good realism within the limits of low airspeed stalls, but not power stalls.
Damage models are still a long way from realistic due to eyes on visibility damage.
However, this conversion has come a LONG way since its beginning.
Red Baron 3D highly tweaked FMs/DMs are the only ones superior at this time.
The_Black_Knight