Okay, some of you may either say 'don't be negative' or 'no one knowing Merlin's magic is the theme of the show' or something along that line, but just... try not to be pessimistic when reading this, save your thoughts for when you finish reading.
Okay, so no main character has discovered Merlin's secret without dying in the same scene since Series 1, right? The last person was Lancelot back in the fifth episode. And there has been... about 55 episodes since then? I mean, come on! Would it even hurt for a character other than Arthur to find out? I have no idea why the producers still want Gaius alive holding Merlin back when they could have another character discover!
I am going to go down the list on how practically every negative comment about the TV show 'Merlin' relates back to no one knowing Merlin's magic.
"Too much repetetivity": If someone were to find out about Merlin's magic it would totally take the show in a new direction and move forward. As oppose of being at the same stage that they were at in Series 1 with Merlin's magic - it has opened up the path of constant enemies within the walls, Morgana seizing the throne in back to back (to back again?) in two or even perhaps three seasons in a row.
"Morgana = Wile E. Coyote now": Well Morgana has been the enemy for three seasons now and little has changed about her mind state since. That has enabled her to keep on trying the same way instead trying new things. That has been a result of mainly her not knowing who Emrys is and her not knowing since she became the enemy of the show. However if she did know of Merlin's magic, it could have made her have redemption much earlier or if not, try new things instead of just striking again like Coyote does.
"Gwaine is becoming one-dimensional": Ever since Gwaine has become a Knight, we have seen little scenes of him with Merlin. And he doesn't crack as many jokes as he did back in Series 3. He's just a loyal 'Knight' or should I say servant to Arthur now. Like when he didn't step in when the brainwashed Gwen executed Merlin to death was just a blow to the heart for Gwaine fans... However, if Gwaine knew or found out about Merlin's magic. We'd see a strong bond once again between the two of them. If they continue with how they are going about Gwaine he is just going to be like one of those extras that get in the shot sometimes.
"Why does the show have to be 'dark'?": Well I think the reason of the show being dark is because of the BBC threatening to cut the show unless they moved the show in a different direction. But if that conspiracy theory were true, they could have taken the show in a different direction by having a character not think of Merlin as just a simpleton - think about it, that would have completely changed the show!
"Uther's mess in 5x03": Well there has already been some debate regarding this episode and by the looks of it, most including myself are saying the way they went about Uther's character in this episode was too hysterical and just... poor. But that is of a result of Overman's poor writing skills, not mainly no-one knowing Merlin's magic. But think about it! If Arthur had known Merlin's magic he probably wouldn't have even blown the horn in the first place! Anyway I think this disaster won't ever be cleaned up...
"Why on earth is Gaius still alive?": Alright I know Gaius has a fair bit of fans, but don't you think his time is over? He is not only holding Merlin back from reaching his full potential, but Gaius still being alive is totally historically incorrect. The average life span for a a wealthy person in the medieval times was about 60. And Gaius is... 95 now? Anyway since Gaius is pretty much the only alive main character that knows about Merlin's magic, and they are too busy trying to not have any other character find out about it, they sorta have to keep him alive otherwise this show will seem like a childish cartoon as much as it already has become. Because if no one knows about Merlin's magic then it would just be silly, it would be like Mr Burns not knowing Smithers has a crush on him.
"Characters like Alvarr and Tristan must not be forgotten!": Well since they are mainly focusing on maintaining Morgana as the sole main villain (and a regular dose of enemies within the walls every seeason or so), they could be focusing on having another or an alternate villain like Alvarr. And like I said above, Morgana being what she is for three seasons has been a main result of her not knowing Merlin's magic. And as for Tristan, since they are too busy giving Gaius and Morgana big roles in episode, it is not only consuming a lot of each episode's budget, but it is taking up the screen-time of what could be a return of a character like Tristan. But bear in mind, this also includes characters like Freya, Gilli, Vivian, etc... And also, like I said above, Gaius and Morgana are still alive and not showing any sign of stepping down because no one knows of Merlin's magic.
"The Mordred in Series 5 only slightly resembles the Mordred in Series 1 & 2": Yup, that is true. But is has nothing to do with Alexander Vlahos replacing Asa, just they have decided to throw all of Asa's work in the trash by introducing this 'Mordred 2.0'. But I think we would have seen Asa more as Mordred in Series 1 & 2 if they weren't trying to keep the magic secret all the time. And this could have enabled a smooth return to Mordred's character later on.
Lastly guys, I know I haven't covered everything relevant to all this criticism that is going on, but I'm afraid there is just too much to write... And there are some elements that are barely related to Merlin's magic being a secret still but majority are linked to it.
Feel free, now, to share your thoughts below!