In 1st person view on any tank or armored vehicle that has a fixed 2d "viewport" for the driver, it is impossible to open the GPS display without opening the hatch and greeting the enemy with an unarmored smile

an inconvenience on vehicles like the Marshall APC, yes - but on the Slammer MBT the driver simply has NO GPS (you can't open that hatch)

that's very awkward, considering the driver is the one who should have the best possible awareness of where he's going... the tank commander? you ask -- nope, he doesn't get to use a gps either, not without popping his head out and/or switching entirely to map view

which is why I always drive tanks from outside view -- it takes a lot away from immersion, alas... (and not all settings allow that)

It is also frustrating that the Slammer clearly features a triple viewport setup for the driver (as seen on external model) - and yet the driver does not have any use of such peripheral eyesight in any way...

Remember how tanks were in Operation Flashpoint? --- now THAT, would be ideal.