I loved the stealth in ZM since you get the gravity suit at the end, giving the maximum Metroid gratification, all those corridors that seemed really hard before can now be crossed like if it was nothing, and no one can stand in your path, that alone was so awesome, and is part of what Metroid gameplay is, I didn't felt it was out of place, and the stealth was handled really well, I never felt overwhelmed by some impossible situation.