Too attractive meaning Facial-Feature no... but alot of time on crap network TV series watdrobe, make up, and continuity are trash.
So they will have actors with perfect teeth and fresh haircuts and plucked eyebrows playing rolls where that is ridiculous. But they won't bother to take the time to fix that using make up, prosthetics, etc.
The other thing is weight.
Thats why even well written shows like Game of Thrones and Lost have fat chatacters that after a season or two really shouldn't be fat anyomre cause they are living on an island or in the icy-snow waking up at 5am doing patrols and going on adventures.