^ Ahhh. Got you. Burton's films, yes. But that would mean a bigger budget. I doubt the show's producers can afford that much hoopla. Even OUAT has poor special effects. So with Grimm baka mutant mutant lang ang kaya ng production nila.

As for the story, I'd say because police procedural has been done over and over, their way of telling this story supposedly lends a fresh take to a format that's quite...tired, like adding those lingering storylines. But I do agree that it's not as convincing pa, kulang pa ng punch.
What works with OUAT is because there's that element viewers know -- the fantasy part, where everyone's dressed in gowns and there's a ball, there's a palace --- all of us can relate to that. Grimm completely did away with that and concentrated on just "real world" stuff, hence hindi masyado whimsical. Which is why it is considered more serious than OUAT.
OUAT is considered superior because it's relatable (at all audience can watch). But if you take away all that fantasy stuff...hindi ko rin alam how it will work with the viewers.
With Grimm filling a one hour show with fairytale-based stuff and writing it down na parang real people sila is challenging. Personally, if I view it from that angle, impressive that the writers were able to do that, sustain it...yung exposition nung characters as real people, mahirap gawin without delving too much on the fantasy part (na ginagawa ng OUAT). Parang after thought lang yung fantasy kasi sa Grimm. Yung OUAT sakop talaga sa story.
Kaya, like I said, it's hard for me personally to say one is better than the other, kasi pareho silang pasok sa viewing pleasure ko. Yun lang hindi ako masyado maka-kwento with Grimm with anyone, kasi the truth is mas patok talaga ang OAUT sa majority, and that I can also understand.
Grimm should've worked, kasi its formula (procedural) is familiar to its target audience. Yung fantaserye sa kanila (US audience I mean) hardly tumatagal. But as it is parang OUAT ang tatagal yata. Mamatay ang Grimm.
OAUT bases its fairytales as we know it (Disney, Cinderella in a blue ball gown and all those stuff! How I love that!

) kasi the network where it's carried/shown is ABC...which happens to be owned by...Disney.
