Little realism/immersion touches like that really sell a game.
Like if the fusion powered tanks sometimes went critical (but could function in a vacuum or underwater) and the cheaper I.C.E. machines couldn't go into space or underwater (different choices, different maps), or hovercraft not going underwater....and of course 'mechs not just going boom but falling on their face, or toppling over, or just ceasing to move anymore...all would be cool.
But that's a LOT of work! I'm willing to do the MW4 thing for a year or more without it feeling cheap (and anyways, we can pester the Devs when they're done with the Beta or first release and are not under such stress....Muhahahaha).