Derailed minecarts sink into the ground
minecarts that go off rails now sink into the ground - also they sit so low that players sitting inside them cannot hit the minecart to get out. also - if said case happens on slabs shifting out no longer places you on the slab, but next to it in the air (if in air) as of 14w10a you can safely get out of the minecart when it's in the ground (but not 100% of the time)