The ruling is based upon whether the person who is trying to repossess can prove that they really hold the loan, particularly if they are not the entity that originated it.
MERS has no standing because they don’t own it.. unless they are being paid to ‘service’ the loan, at which point they do. The problem is.. can MERS prove that they control that loan (paperwork trail?).
During the real-estate madness heydays.. I don’t think that many people were keeping the paperwork in order.