Comment Re:Hooray for standardized hardware (Score 1) 75
A socket adds a significant amount of parasitic capacitance and inductance. At high frequencies, this can cost quite a bit of power. You're right about it also contributing to space and cooling issues.
BGA has among the lowest parasitics of all IC packages so it's not surprising to see it everywhere nowadays. Except for how hard it is to desolder, it is an awesome way connect ICs to PCBs.
Contact area (wire size) doesn't really matter... Your connection needs to be big enough to handle the worst case power and no bigger -- any extra metal is just wasted (to a point, but let's not get pathological discussing running 1 GHz signals down 0 gauge wire). The path of the signal tends to be much more important than the wire size.