Hey, Dmiraie, this is definitely a fun topic to think about. When you proposed that hypothetical challenge from Michael Bay, I had a good laugh. My first thought was to recommend that you composite in a couple of explosions, do some more compositing and have the members of the band sitting on / standing amidst some military vehicles, add environmental efx like smoke/fog, especially some blinding rays of other-dimensional light piercing the smoke (... hey, wait a minute, I already did that ... LOL), and definitely composite in some sexy chicks to round out the mix. If one of the road cases was emitting jets of steam and starting to open up and transform itself into a large Marshall speaker stack, that would be even better. 
Now, kidding aside, all of the above is quite do-able in PS. A major part of the work / skills needed involves compositing in PS, but there are a huge number of other skills necessary to make the compositing look realistic (e.g., simulating shadows, accurately cutting out the component images, and when pasting the component images into the composite, adjusting the light on each component (color, intensity, direction, directionality and size of the light source, etc.).
Obviously, even just one the above changes can't possibly be done in 20 minutes, even by an expert, so going along with the challenge you posted, one is left with fairly simple, less time-consuming approaches. The problem is that there are so many of these to choose from, everyone is going to have their own idea of which they think is the best. This is why there are so many different genres of album and publicity art. I kind of like the second tweaked version that I posted (blinding orange light from behind), but, without a doubt there will be lots of people that either hate it, think it's blah, or inappropriate for album art / publicity use.
So, since there are so many different viewpoints on this, and executing each of these will require a significant investment in time, my suggestion is that you start a new thread titled something like:
[Challenge] Turn this straight Iron Maiden snapshot into slick/commercial/overproduced album art.
Copy over some of your previous explanations into the body of the new thread. This way, you might get more people to illustrate their own visual preferences, and interpretation of the challenge.
There are lots of folks here that are good at compositing, so you might even see some of that, but I'm sure you also will see plenty of other approaches that don't involve compositing.
Me ... I've committed doing several hours of much more mundane (event) photography tomorrow, so, for the purpose of this challenge, I'm going to stick with the tweaked image I produced earlier.
Have fun,
Tom M
