The Villa performance had blinded people a bit. He had very little defending to do and wasn't put under much pressure, which allowed him to continue with his passing. Don't think he was great against the Spurs.
Blind is an intelligent player, who understands VG's "philosophy", what ever that is, better than anyone else. So, in a way, not a surprise that he hasn't looked completely out of place there in a team that is basically plays with 6 defensive players. The FB's don't bomb forward or overlap, sometimes covering for the CB's. Both the CM's sit close to each other, protecting the defense. We have an ultra-defensive set-up right now, in which he hasn't been exposed yet.
Much sterner tests lie ahead. There will be games where the opposition will score first or games we are drawing, where we'll have to lose our defensive shape, the CM's and FB's will have to be more aggressive and join the attack: Will he be able to cope without the extra protection that was afforded to him last game? Will that expose his lack of pace and physicallity like it was against PSG? Will we be able to keep the high line against tougher opposition? Will he be useful when we are under the cosh and are bombarded with crosses in the box? How will he look when he has actual defending to do? Will it work with Jones?
Those are some of the questions, the answers to which make me very uncomfortable about his suitability for the position in the long term.
I am sure "90%" of the forum, including me, who are skeptical about the idea of Blind playing at CB will be delighted if proven wrong, as being incorrect would mean that we have finally found a really good CB partnership in Smalling and Blind.