Sorry but RAM does and will fail and normally its no biggy - you can get replacement RAM at a very generous price these day and just slot the replacements right in? I literally do not understand the people who are screaming "WHO CARES!".
If I'm wrong in this assumption please correct me but say you purchase a MBP with soldered RAM and do not wish to take out Apple Care. You've had the machine X amount of time and it is no longer in warranty. The RAM fails and its soldered to the logic board. You need to go to the Apple Store where they will charge A LOT as they need to change the entire logic board. Opposed to just simply swapping bad RAM sticks yourself for a fraction of the price it would cost to do the above?
In addition to this, on the Apple store right now to upgrade to 8GB RAM on the non rentia model would cost an additional £80. But I go onto ebuyer and could get 8GB RAM for half of that price. How can anyone say that isn't ripping off the customer? If Apple decide to solder RAM to the logic boards of all their future products this effectively forces the customer to purchase the maximum RAM spec at the time of purchase. HOW is that acceptable?
This is just another elaborate way of forcing you to stay up to date with Apple's product life cycles. A money making scheme simple as that, in my opinion.