I binged it starting a few weeks ago and finished it last week.
I enjoyed it for the most part, although I have seen that Netflix cancelled it, so it's done for good now. I am glad that they got to have a Season 3 in the first place, and I think it had a good ending, and one which you can end a series on, although they certainly established some storylines for a possible Season 4.
To me, it shows how important and vital a showrunner is to any TV series, and incompetence or brilliance can really effect the course and destiny of a series. I read that "DS" went through five different ones before it was over and done with. I do wish that they would have stuck more with the conspiratorial mystery aspect of the show, as I think it was at its best when it did that, as opposed to being more of a "West Wing" type of show.
RIP Designated Survivor. It's too bad it took so long for you to figure out what you were.
The showrunner changes and overall shift in tone didn't help, and neither did the revolving door cast (although I suppose that was one of the things about working in the White House that they really got right....high turnover there).