That is excellant work, realistic looking damage and good rusting effects. Damage (particularly to that level) is not easy to get to look realistic, but you have managed it brilliantly there. I can tell a large amount of thought, time and effort has gone into it.
With regard to doing this to a good kit, I think the hours invested in making such a great diorama makes the kit value pale into insignificance, so is a good use of the kit to make such a high quality interesting diorama in my opinion.