I think the primary issue for many of us that don't necessary know a 47 inside and out (or even a few who do but can see past the issues) is that a lot already have a recent Bachmann example. If we then were to go out and buy a Heljan 47 you wouldn't want to put them next to each other or your eye will notice something off, even at a bit of distance, arguably more the roof that anything else due to common perspectives. By itself it looks like a good class 47 from any reasonable distance but put a Bachmann 47 there and by comparison there's something not the same when there should be. People will therefore be somewhat inclined to stick with one example going forward and in many cases that will be the Bachmann example.
Compare this situation with class 37's. I'd have much fewer reservations about mixing Bachmann and Accurascale 37's as the difference is really not noticeable IMO at much distance even if I do have a slight preference for the Accurascale rendition (with improved sound and no nose seam, finer chains, light dashboard). Those differences are not deal breakers if the right livery comes up on the right loco in the way that this 47 is for me.