"seem fantastic" is a correct and usable phrase in written English.
You can use it when you want to express that something appears to be especially good or exciting. For example: "The view from the top of the mountain seemed fantastic!".
They made 3-D TV seem fantastic.
But what can seem fantastic — or at least far-fetched — often turns out to be fairly routine in the worlds of these subjects.
He was born in a place we barely know, where what used to be mundane can now seem fantastic: Uruguay, almost a century ago.
Miller is also very good on how Murakami can make the everyday seem fantastic and how he brings solidity into the novel: She writes: "In American fiction, the sanctum of the literary must not be polluted by the trash of commercial culture -- not, that is, unless it's coated in a protective layer of satire.
Fast Company billed itself as a "workstyle" magazine, tying the rising obsession with work to the aspirational nature of lifestyle magazines, and indeed the pages of Fast Company are populated with people whose lives are meant to seem fantastic but faintly attainable.
For us the views of medieval scholars seem fantastic, unjustified, useless, so "non-scientific".
What to a biologist is perfectly reasonable seems fantastic to the untrained.
"Sometimes you put a good swing on the ball and find a gap, and everything seems fantastic," Rollins said.
After the favela the debate seemed fantastic to the writer in its preoccupation with tax cuts and prosperity.
"Even under the grime the detail and the colour seemed fantastic, far too good for a mere copy.
Such a task must have seemed fantastic in 210, but Scipio had the confidence and ability; it was achieved in the next four years.
