Here's my take on things.
As it stands, Tom Holland is the clear cut choice. On the surface, he just has more of the qualities needed from a Spidey actor. He has great physicality and athletic ability, he's a great actor, and his rather chipper, enthusiastic, and fun loving personality lends itself to the Peter AND Spidey sides of the role.
Asa on the other hand is a HUGE question mark. We know he's a phenomenal dramatic actor, and he has a more traditional look for Peter, but we don't much else about him in regards to this role, and if he has the qualities needed.
We don't know if he can pull off the physical aspect, and we don't know if he can pull off the comedy, since his typically dry, monotonous nature doesn't lend itself to that.
That said, if Asa does have those qualities, and or has the talent to portray them, the he's easily the perfect choice.
So, just going off what we know and have seen.... they should pick Tom. But if Asa wows them, and proves he's better than Tom seemingly is, then by all means, he should be chosen.