is new talon a viable top laner?

Viable? Probably. Good? Probably not. So much of his power comes from roaming, and roaming is so much better from the midlane

He's strong at early levels as his passive does serious damage, and his W and Q now too. However as his base damage scale up less than before, he's quickly going to fall off in a laning phase, as his E gives him no fighting power. Additionally, his power now lies in his roaming, which you can't do as much from toplane as you can from midlane.