Hi RJ,
You've obviously put a lot of time into the finish and achieved some interesting results. However, you need to think of the context that the vehicle is operating in. This would look fine if the vehicle had been abondened on the battle field and left for some considerable time, but for an operational vehicle I thinkit's a bit OTT.
In general tanks were well maintained, with the crews constantly working on them to keep them operational so large areas of rust simply wouldn't be allowed to build up, otherwise the crew would find themselves in the Guard House PDQ.
If you opened the hatches and added a deserted feel to the vehicle I think this would work.
That said it's good to experiment, you could add some MIG dust, Light Sand and Brick Dust to give it that final left behined look. At the end of the day it's your kit and if your happy leave it as is.
Hope that helps.
Al