I think that the Vulture is going to be a lot lighter than the FDL, more Viper sized. More like an alternative to the Viper, than a size increase from the Viper like the FDL.
I do think that both are going to be combat-leaning ships.
The Vulture is supposed to get 2 Large Hardpoints, I can't see it as small as a Viper. I think it'll be as big as the Asp, if not bigger.