It looks like they are saving space, that's my take on this. On the S4, they had separate slots. On the Note 3, they piggyback them. That was a space saver, more room for something else. Most likely, the spring would have blown the design.. Also, we are not in there snatching out sims or sd cards 3 and 4 times a day. In fact, this is a very SELDOM move. IMO, the designers figured that too and went with this.. I put my sim in, my 64gb sd card, and I am finish with that slot. It will be a rare thing for me to have to go in there in the next 6 months..
IMO, if it is a problem getting the card or you damaged one, the next one, I will be at my carrier's place and have them do it.. Once it is in, forget it.. Just my take.