Personally I don't think it'd be great.
I can see Vect on his dias as a Chariot, but for an Archon to really be effective, he needs support.
I sincerly doubt that GW would allow the Shadowfield to remain at full strength and work for the whole Chariot, but in that case the chariot itself is incredibly vulnerable ane makes the Archon a fairly week target. As it is Archons needsa unit with them to take for them, but a Chariot would go down really easily, especially at the armour listings you've proposed.