Radt, this is beautiful: "How can that be an insult to God? In fact, God is there in each and every human being." Yes, yes, exactly!
I can understand how some people might think that mytho fans are just idolizing actors, or that actors are trying to "be God," but really...you can be irreverent and "insulting to God" with anything. I can have a beautiful japa mala or murti in my home, but if I spend all day polishing it and admiring it and thinking thoughts about how wealthy and amazing I am to be able to have such a nice thing, then I've just made a holy object into something awful.
And on the reverse side - when Lord Shiv drinks poison, it's nectar.
If you watch mythos just to look at pretty costumes and fun sets and stare at nice-looking people, then yes, you're probably wrapping yourself up in maya instead of growing closer to God. And if I make the time to watch serial episodes, but say I don't have time to do japa or puja or observe holy days, then I'm doing wrong. But that isn't the fault of the mythos actors, producer, or director. No-one else can distract me from the Supreme if I am determined to be devoted! Only I can do that!
Personally, I am so glad the serials exist. The two that I have watched, have taught me so much and have made so many stories come to life! They are wonderful for learning! I'm a western Hindu convert, and when I first started seeing Om Namah Shivay, I would watch just like a little wide-eyed child. I'd see an episode, then go look up the stories or the characters online and read all about them. From there, I'd read parts of texts like the Gita or the Upanishads or whatever I could find that would teach me more about who those "characters" really are.
It's hard to learn about a completely new faith, but with serials, I had a clear place to start and a logical order to follow, and the stories were much easier to remember after having seen them. Also, there is a lot to learn when you're first starting out, things that aren't necessary to love God but do help you not look like an idiot. You can laugh at me if you want - but I'd never seen a diya or a tilak or a puja tray and had no idea what these things I'd been reading about looked like. I didn't know what modaks were or how a dhoti looked or how married ladies put kumkum on their partings. Serials teach about culture and history, not just religion - to youngsters just learning about the world, and to silly newbies like me.
Regarding signature lines, user pictures, etc.: I don't know if this is the right way to look at things, but when I see an excellent performance, I think that I must be seeing a tiny shadow of the Deva's real glory. I think to myself, "If that actor is so great in this role, how many million times more wonderful must the real Rama or Shiva be??" So the different user pictures are kind of like lots of different tiny murtis in a row. The images remind me of God, not of actors! Same with the signatures - as fabulous as Samar Jai Singh was as Lord Shiv, I don't see panchakshara mantra in someone's signature line and think devotedly and lovingly of him. :P
Anyway, the Natya-shastra of Sage Bharata came from knowledge given by Brahma, at the request of Indra and other Devas, and is sometimes referred to as the fifth Veda. And its subject is theatre, dance, and music! How, then, can a serial full of acting, dancing, and singing - especially with the goal of teaching lessons and devotion of God - be wrong? If a person has an artistic talent and chooses to enact the Devas' stories and graces and glories, isn't that the best possible use of that talent? And aren't those stories the best possible "theatre, dance, and music" we could be watching?
Just my opinion. :)