CMRT: tank combat seems way off

[A Canadian Cat]

Could the skill setting have a big impact on how spotting works in hull down? I've seen people suggest that Iron and elite settings can cause unrealistic issues with spotting targets?

No, the skill settings do not change who spots whom at all. I guess there is one that reverts to borg spotting but even then it does not effect the initial spotting process it just makes the information instantly shared with all friendly troops.

Also the differences of spotting between the commander hatch being open compared to when he is looking through a slit could have a drastic impact (Which everyone here has most likely figured out)

Absolutely, tanks have had their ability to spot tuned down since the initial release - because viewing the world through view ports is very restrictive. Having the hatch open and a head out makes a large difference. Couple that with one half of the defect regarding hull down was that all the eyeballs in a tank were treated equally (or at least not differently enough) so more eye balls meant better ability to spot things. However not every seat in a tank has the same ability to see. Some seats only have a restrictive view in one direction and others have 360 degree views. So with the hull down tank the guys in the hull cannot see anything and therefore that thank only has the turret crew able to spot things. If the turret crew, who usually have access to better view ports are treated as equal at spotting as the crew in the hull (when their view is not blocked) then the hull down tank will spot less well than the tank in the open by a larger degree than it should.