In the case of Narkasur I understand that it might be to show that he has been 'tapasya mein leen' for aeons, so long finger nails, unkempt etc - this is okay. Hopefully, they will give him a better look.
In the other show which shall not be named, they had really handsome looking Asurs and it did not take away ... but added some more dimension. The fearsome negative qualities had to come through with good acting.
Even in Mahakali, as much as I did not like the Bhandasur episode, the actor depicting Bhandasur was good looking, no overt ha ha ha etc, but you sort of felt the negative aspect with his performance. It was creepy ... and that is what was required.
So what is your opinion?