This could be either really good or simply meh.

It all comes down to what they retain, improve, and add.

Retain:

The sense of flight and the flight models. RoF, for all it's failings, is a helluva flight simulator. Heck, I practice in RoF for things I want to fly in my Real World 7/8ths scale Nieuport 11. Yes, it has an inline engine, but other than that - and it's much less an effect than one would presume - the N11 in the sim and mine fly pretty much the same.

Wind effects. RoF is probably the first sim that gets turbulence and gusts that feel right, IMHO.

Improve:

Unleash the AI. Good gravy, the Beta AI was loads better than the release one, and it only got worse with updates. I guess people complained when the AI, at higher levels, would extend away during a fight, attempt to climb away, and lower AI would actually run away if it got the chance when damaged. This was replaced with the knife fighting to-the-death AI we have now.

The weather system. Please, for the love of Fonck stop sending up missions into gale force winds with sheets of rain going sideways and half mile visibility. They didn't call it the Dawn Patrol because Captain Tennelle was in the Escadrille. They flew at dawn because that is when the weather was most favorable to flying...and more importantly, landing at the end of it. The air is less turbulent, which means recon aircraft can do their jobs better, particularly if they're trying to take photographs.

Draw distance. Sigh. I thought IL-2: FB had the right balance between prostituting contacts and making the enemy jump scare one. RoF's is just weird. Zoom in and the plane is easier to detect over distance; zoom out and they disappear. It's weird.

Add:

A more "campaign-y" campaign. I don't have a lot of gripes with the current RoF campaign - squadron management and stuff leaves me cold - but it's without context. Even when the front was static, there were specific over-all goals for the Air Services, either trying to hide reinforcements and artillery movements (and thus more scout interdictions of two seaters), trying to find out about the same (escorting two seaters), going for rail heads (escorting two seaters and bombers), or air superiority. It would be nice to know why I'm flying the set of missions in general, if not particular.

More aircraft in flights. Later in the war in particular, both sides had flights of 40 aircraft each stacked at different altitudes. Even if they halved it, it would be an improvement. Four on four was pretty rare.

"Little green men" running across the front. In Red Baron II they had them, and even though they were kind of cheesy sprites they added a lot, and when RB3D came out and they disappeared we all mourned for their loss. IL-2 had little men that would run from vehicle columns when one strafed them as well. Populate the world with little sprite men and stuff on the roads. If it makes the censors happy, make the horses indestructible and stand still, unharmed, in front of a burning wagon if you have to.