I also agree with the first 2, BT is inconsistent, i hate the keyboard and i would easily switch it with my MBP 2014 one. Screen is fine for me, and it overheats so much that does not have this cold metal feel. :D
In general i can live with the all the aforementioned, but i hated the previous 2 year period with the random Wifi disconnection issues; it sometimes made my work unbearable.
Hence, i would say that the biggest issue with MBPs is the deterioration in apple software.
I had the same problem with my 2012 MBP constantly overheating until I recently opened it up and removed a pad of dust that had accumulated between each fan. There was no way for the hot air to escape anymore. Problem solved, I've not even heard the fans run once since.
In general i can live with the all the aforementioned, but i hated the previous 2 year period with the random Wifi disconnection issues; it sometimes made my work unbearable.
Hence, i would say that the biggest issue with MBPs is the deterioration in apple software.