I thinke the kit is modelled well but, it definitely needs a highlight layer or two. If you added a first layer of say, shadow grey and chaos black 1:1 on the edges followed by a shadow grey extreme edge highlight it would make all the difference. Try using the flat side of the brush on the edges to get nice crisp highlights. You definitely don't want to do any drybrushing on the black as it's very unprecise and would make it a grey templar dreadnought. If you do want to drybrush your highlights on it because its easier than direct edging, make sure the brush is almost totally dry before you put it to the model.