I've flown the 111 in CLoD, and did a bombing mission, hitting my target, but its like only the 2nd time I've ever flown the plane. The 88 in CLoD, I've flown 4 or 5 times, but I only ever dive bomb with it, so I dont know about its level bombing. Funny, I can hit targets bombing in the 111, 88, 87 and 110, in CLoD, but cant hit the broad side of a barn in ROF.
There a lot of factors that screw up the settings you might use for the bomb sight in RoF, mainly in the 2-seaters. Depending on the plane, the readings that you're getting from your instruments can't be directly entered into the bomb sight; they have to be interpolated, which can be a complex process. The Breguet used to have some issue that I can't remember; others have TAS/IAS issues, and altimeters read from sea level I think so the elevation of the target can produce inaccuracies that get worse with higher speeds.
The Gotha is kind of an exception to this, since the readings pretty much can be entered directly; also it is slow, stable (in autopilot), and you have the front seat to jump into to help yourself initially line up the target run. These are attributes that most of the 2-seaters lack in one area or another. I suppose the HP O-400 is about as good at level bombing as the Gotha, but a big part of that is that it can't really climb higher than 2,000 m, it carries a bigger bomb that a lot of people use to circumvent the need for accuracy, and it's bomb sight is a bit fancier with respect to it's ability to factor in wind direction.
All of the bomb sights in RoF are extremely unrealistic compared to the actual sights that they used in WWI, which were far more primitive and ineffective. The only one that's similar is the transparent wing panel on the Strutter....and it still is able to use the fancy advanced sight that the rest of the planes have.
The expectations most pilots have for bombing success in RoF are far different than they actually were in WWI. An example of a "successful" high-altitude bombing mission in WWI would have been more like, you made it to your intended target, you got over it, and you dropped your bombs: mission success. The idea that you actually hit something, or at least a specific object you were aiming at, would have involved extreme luck. If they took away the uber bomb sights and gave you points for just putting your bombs in the general area, it would make more sense, but people would probably consider it a lot less fun too.
The low-altitude close-support bombing that we do in RoF is actually the only thing that equates to actual WWI tactics that might have had any real effect (other than psychological), and was done by the Camels and Halberstadt CL series planes in the trench areas.