And you would also have to assume that God is not omniscient to conclude that "very good" was intended to apply only to the pre-fall creation. (Indeed, one of the conundrums of Genesis is its depiction of a contrarian and oddly limited God, who was, for example, unaware of the location of Adam and Eve after they succumbed to the temptation that He had orchestrated for them.)
No such "have to"...
God saw all that He had made, and behold, it was very good. It WAS very good, pre-fall. Man had free will, but he WAS still good, with the potential to choose sin. This potential is not a flaw. If it wasn't there, we'd be automotons.
The alternative? Just toss the basis of all Christian religion, and that is the whole goal anyway, isn't it?