I totally disagree! I thought Episode 4 was one of the best. Whilst the air battles are brilliantly done, there's only so much of it that can be shown without it getting repetitive and potentially dull.
What episode 4 showed very well was the experience for the many others involved in the campaign - the mechanics, ground staff, pilots not on mission for whatever reason as well as friends and lovers - they see the planes go off, and then its just waiting anxiously to see who comes back. And not knowing whether someone is dead or managed to bail out and survive. Trying to piece together from fragmented reports what happened.
Not knowing what happened to their comrades was a key part of the experience, even for pilots on the mission (also covered in episode 5 where the sole surviving plane couldn't understand where the others were).
It may not fit a neat narrative, but so what?