Yes, it's true, most people did not like the last episode! Here is why I think this happened:
We were told from Colin, Katie and the others that all the questions would be answered in the finale. However, almost none was. We never learnt why Aithusa allied with Morgana. We never learnt why Aithusa is the light of the sun, and why she means good for Albion, since the only thing she ever did was ally with Morgana and help Merlin's greatest enemy. In addition, Kilgharrah and Aithusa disappeared in the finale, and we learnt nothing about what happened to them afterwards. I could go on and on with the plotholes.
However, there are those who do not care about the plotholes and enjoy the show for their favorite characters. They, too, did not like the finale, because characters with huge fanbase died. Although Morgana and Mordred were on the bad side and their death was necessary in a family show, the death of Arthur and especially Gwaine were really unnecessary!
Finally, all the destinies were unachieved. Merlin failed bringing Albion, Morgana failed bringing back the old ways, Arthur failed in bringing Albion as well, and the only one who particularly succeeded was Gwen, because she remained the queen. However, without Arthur and an heir, she, too, is bound to fail, along with the other three main characters, and this is really tragic. Merlin became a postman, Arthur, Morgana and Gwen die, with no Albion created. How is this an ending that people would love to see?
This is why I think people hated the last episode. Unless we see a movie or something, that the characters are reborn to modern era and Albion is indeed created, nothing can redeem this show anymore. What are your thoughts?
P.S. You can call me Chris :)