I actually liked the ending even though it wasn't historically accurate. As for the final season, I agree 100%. It was definitely a let down in comparison to the rest of the show. I had read that the show got killed off early and somewhat unexpectedly because it was very expensive to shoot, and Terrence Winter is going to start working on another series about '70s rock and roll, so they rushed to tie everything up in the last eight episodes instead of the normal twelve episodes per season. I believe that they had originally planned at least two more seasons of the show, and instead gave us 2/3 of one. That definitely made it feel unfulfilling in a lot of ways when certain storylines just evaporated with a gunshot or no closure in some cases.