why the frak does everyone think Kara's dad is 'Daniel'?
there's no evidence to support this . . .
There is plenty of evidence to support this, this episode went 80% of the way towards confirming it.
Daniel was an artist, Dreilide was an artist. Anders wrote Watchtower while on Earth, Dreilide (one of Ander's "children") knows Watchtower and taught it to Kara as a child. Hera knows the notes of Watchtower, that suggests a connection between her and Kara; they're both hybrids. Kara was reborn somehow, possibly using some sort of Cylon resurrection technology. Leoben knows that Kara is special and has a destiny, perhaps a subconscious understanding of Kara's relation to the rest of the Cylons.
Finally, if Dreilide is Daniel then a quiet character moment from the beginning of season 2 will actually have been one of the most important scenes of the whole show. It would tie things together brilliantly, so maybe there is some wishful thinking going on.
Plus, Tigh being Kara's "grandfather" would be incredibly rich.