This was the 100th - and final- episode of Blindspot. The true reflection of the show's decline is that, to date, three days after the airing of this final show, there are only half a dozen reviews here. In the "old days," especially the first several seasons when the show was good, there would be dozens of reviews and comments on each episode. There is a reason for that dramatic fall in interest for the show - it was no longer very good.
That said, this final episode was somewhat better than the previous shows of the final run, admittedly a low barrier to surpass. It was an interesting choice to bring back most of the show's distinctive characters from the entire run, mostly dead now, so they were either ghosts or hallucinations. Unfortunately, it did mostly serve to point out "Oh yeah. I remember him/her. That was a good character." For me the downward turning point in the show was allowing the Sandstorm conspiracy to linger much too long. It seemed as if the writers just delighted in jerking the loyal audience members around with that story line and its twists. Instead, it moved into a "who cares" mode for most. By this 100th episode I thought both Jaimie Alexander and Sullivan Stapleton looked tired and worn. Perhaps they wanted out, too???
It's very hard to write well for a show such as this for five years and make it fresh and entertaining. It was a good concept. Ultimately, it just got worn out. It probably should have ended at least one season earlier, perhaps two. Alas!