Base on my personal analysis, i think that McGregor will win the fight. Judging from the physique, fighting style and fighting mindset, for me mcgregor has an advantage. I bet he will knockout poirier.
McGregor is one of best fighter we have in last few years he can win this match but still all predictions are too early because any thing possible in a match Poirier is also very good fighter and he can do upset in this match.
Connor has a big advantage in this fight, Porier will likely get KO/TKO under 2.5 rounds. The bigger fight would be Khabib coming out, Connor doesn't want that - he would get destroyed again. There is a pretty clear #1 and #2, and then everyone else.
Now after death of his father he is already announced retirement most chances he will not came back and fight with McGregor because he announces his mother want to retired from this and he done this for Mother.