Unfortunately, war always comes with death and destruction. Therefore building dioramas with dead soldiers or falling soldiers is normal. If you are building it for yourself, I think you should go for it.
Yet, if you plan to displace you dioramas in the public, say in a model show, I suggest you to take some pre-caution in presenting them. Modeling death in a diorama might involve certain gore and bloodshed. If this is present in a overly exaggerated way, it could generate replusive feeling on viewers.
I can give you an example.
Back in 1981, I attented a public model show in Hong Kong. There were several dioramas involving death soldiers. Most of them were presented in professional way. However, there were four of them that are so disturbing and controversal that they were ordered to be removed. Why? It was the gore and bloodshed involved were so exaggerated and eccentric that most viewer could not stand. They can be described as following
1) This one contained two Airfix 1/32 soldiers, one Japanese and one British. The scene showed a Japanese beheaded a British soldier during the fall of Singarpore. The red paint(blood) used was overwhelm. Way more than it should be.
2) This one also contained two 1/32 figures, one Japanese and one GI. This scene showed the Japanese soldier bayoneted th GI to death. Not only the gore was overdone, the modeler also scratch built the guts and internal organ of the GI. Again that was totally unnecessary.
3) The scene in this one showed a German Panzer 38(t) ran over a Russian solider. You can imagine the gore involved. The Russian soldier collapse was scratch bulit(by some putty or plastic sheet I assume).
4) This one showed Alien(yep, the space monster in the movie Alien) ate up a human being. Well you could see Alien holding broken human arm and leg on it's hand and on the floor with a human broken skull with brains smashed(made by plaster)
All four dioramas were built by the same person.
The officals in the show considered these four doramas, built by the same person, should not be showed to public due to the graphic nature. and I agree. There is a difference between showing horror of war and using exaggeration in gore to gain attention. That is why movie like 'Saving Private Ryan' and 'Passion of Christ' are prasied and movie like 'Toxic Averger' is critized. It is the intention of the builder we should forcus on.
Furthermore, that modeler was insensitive. Expecially, showing diorama #1 and #2 in Hong Kong where the Japanese troops committed lots of atrocities during the war.
It was very sad. I had seen this modeler's dioramas before they were removed. I can tell he was a very talented young man. He surely did not had to do this(boy God know how many bottles of red paint) to gain attention.
Fortunately, the above is only a very extreme case. Most of the dioramas I have seen are presented in a professional way with resonable gore. Andy, I am confident you are a professional and mature modeler like all of us. When you complete your diorama, show it to us. Thanks.