Lowest scored GOTY nominees.

[curl-6]

Bayonetta 2 was the best game of 2014, but Mario Kart 8 and Tropical Freeze were right up there as well. Captain Toad was awesome too.
Wii U's 2014 was damn good and the only year of the system where it really felt good to own one.

My tastes are a bit weird; my top game of 2012 was the Wii reimagining of Fatal Frame 2, at 77 on Metacritic. Binary Domain would be up there as well, and that has a 72/74 on PS360 which is downright criminal.

As to the actual questions, I think this year has so many 90+ games that I wouldn't expect a low 80s nominee, and it's too soon for me to pick one.
Street Fighter 6 seems the likeliest pick for a 90+ snub.
This year is pretty packed in terms of the sort of highly acclaimed blockbusters that get nominated for GOTY awards, though personally I have my eye on smaller scale stuff like Turbo Overkill and Phantom Fury which tend to be ignored because of their modest production values. I expect the former especially will be almost entirely overlooked despite it looking incredibly promising.