As harsh as he may seem, Fester actually is trying to present the idea that you don't just put a flat color for BMF. He said he won't spell it out, but allow me to try.
BMF is one of the hardest "looks" to pull off. My first attempts were quite bland. I think I got better with my more recent ones, though.
Let's look at your examples here:



Look at them. They have a wide range of colors, highlights, shadows, all on a single frame. It's these "effects" that you need to try and capture in your BMF pattern. Look at some of the P-51s and P-47s for example. Some folks really have this down. Others not so much.
The end result can either look like a solid color paint bucket fill, or it can look like dynamic light off of a metal surface.
I hesitate to severely criticize other people's work, so I'll just classify the metal only (and not the overall skin).
Just using the P-47s as an example... Here's a paint-bucket-fill consistency skin:

Very blah. Markings may be nice, but the skin's BMF leaves little for the eyeballs.
Here's another one, with better BMF:

You see how it doesn't look like a 2D bitmap? It has extra depth. It's not just the rivets and panels. It's not just the weathering smears... It's the actual effort you put into painting the BMF itself.
Now for my own personal examples:
My first BMF:

I tried to give it a bit of that definition but I didn't "get it" at the time. Overall I find it bland nowadays compared to others.
Now my next attempts I tried even harder:


But overall I think it still left a bit to be desired.
I think I finally "got it" with my later ones, as seen here:


So you see how you can have a nice nose art and tail codes, but the overall skin can still be bland? BMF is very hard to get right, and it takes a critical eye to keep yourself on track. Either you have that eye yourself or you rely on outside feedback (which I would hope you do anyway -- many times I thought I was on the right track only to have folks steer me back on course, and I even scrapped and redid my later P-47N efforts for a much better end result than I initially had thanks to forum feedback).
Kev367th showed how he did his and it was quite impressive and helpful -- this isn't for the detailing just the base underlying colors, even!
The link is here:
http://bbs.hitechcreations.com/smf/index.php/topic,179337.0.htmlbut the image is broken. I think I have a copy of it saved at home but it will have to wait until later when I can check, upload, and repost it here.