I don't like using Teneb as it's a bit mana intensive and you can't res something scion is copying.
Yeah, Scion just pitching and abusing Bladewing and Teneb is pretty standard tech, along with things like poison instant face burn.
I much prefer big daddy Ur-Dragon's "I just put 30 CMC of bullshit into play" way of doing things. It's a very slightly more honest (and thus much less likely to win, admittedly) approach.
Ur Dragon does sound more thematic to a dragon deck as scion ends up distorting the deck around abusing him