If he has a significant role from day one, get him.
If he will not play a role on your team on day 1, don't mess with him.
As has been mentioned, he will not improve much. Maybe 1-2 in a few areas. But if he could start immediately, take him. Not a bad guy to fill out the roster with.
One year at a high a plus school in d1, I took a project with high work ethic and a stud with a 10 we.the project played sparingly year one and the low we played tons. Year two, it was pretty even, year three the high we guy was a stud for me and the low we guy was helpful off the bench, year 4 the low we guy played little, while the high we guy was a top draft pick. Worked real well having those two guys recruited together.