The first season was the best for me, totally new not knowing what will happen next etc. The whole season was like a pilot to the second. The second was the peak of the story, the grand plan, everything is shown, we finally know what was happening all along. The third was a blunder remake of the first in a way and since then the show is nothing like before. I would suggest to stop watching it after season 2 if you want a strong end.
Review of Blindspot
Blindspot
(2015–2020)
First season 10/10, second 9/10 and the third and fourth below 5/10
16 February 2019
Warning: Spoilers