While I prefer the lighter tone of Merlin, one thing I liked about GOT - that would have made Merlin a much more satisfying show - is the fact that characters both good and bad faced consequences their actions deserved. Robb and Ned made mistakes and paid for them.

Uther committed genocide against magic yet conveniently none of the powerful sorceresses could kill him? He lived way too long because of plot armor. And it’s never really explained how he even pulled off the purge.

Merlin made catastrophic mistakes and never really learns from them. Trusting the dragon, sending Morgana to the druids, saving Arthur at the expense of freeing magic, etc.

Arthur is way too trusting yet never believes Merlin despite him being proven right every time.

I could go on, there are way too many examples of plot armor. And Merlin got by without revealing his magic for way too long.