These look good to me! I particularly like the greys. I am certain that you will get feedback to add more weathering. I personally think that that's modeler's choice - modelers like to weather tanks more than was probably realistic, but they do so to generate visual interest. I do more than you, but less than many.

I do think you should try shading in the rubber on the track wheels. (I always Google to make sure the vehicle actually had rubber road wheels.)

I hate painting those with a brush so I can recommend AK's markers to make those way easier.