The heat generated by newer generation low power CPU's is obviously less and aluminium construction helps to dissipate the heat quicker,and besides the cushion puts the keyboard at a more acceptable typing level.
I also thought about it that way but besides for installing games I dont use optical media anymore so I guess I can do without it,yeah sure its not as practical anymore but for me personally I cant see it as a deal breaker.
Thinner looks better and is easier to make lighter,physics will see to that....remember for the structural integrity of a thinner laptop to be kept in check by the chassis it has to handle less shear/stress/strain than for a thicker laptop design.
I usually prefer function over form but in this case function will eventually catch up with form just as it always has in the pc world
If we did not continue making pc's slicker just imagine what we'd be sitting with now.