The problem with the spear being Finesse in 5e is that since it has the "thrown" property, it basically turns the spear into a version of the shortbow that is versatile, and can hit in melee.
That's a valid counterargument, although to be fair it wouldn't be quite like a shortbow because of course you can only throw as many spears as you have in your inventory, which wouldn't be too many unless you really want to cheese it. So far, sadly, the spear has none of those properties, so I guess we will have to wait whether Larian has planned anything for it. In general an interesting way to incorporate both versatile and finesse could be to allow players to use spears as a finesse weapon, but only if wielded with two hands. Once you use it one handed, you would have to use it with Strength.