And by this SAME argument (i.e. Johnson being a potential cancer that would really hurt the team), then Freeman is basically the "anti-Johnson," in terms of how he leads the team, buys into Pikiell, and the effort he exudes by example. But for which you give him no credit, only looking at his missed FG attempts (just 1 part of his game).
One poster argued Freeman makes his team-mates better ... and another poster (not you, I do not think, though you may have agreed) argued Freeman does not make ANY of his team-mates better. I would argue that though Freeman does not set up his teammates, or pass that well out of the double-team, the way you - and frankly, most of us - might want ... the classic way to make teammates better, he DOES make his teammates better through other ways:
1) Leading in practice, by example.
2) Leading by example in games - in particular with his unrelenting effort, but also with his enthusiasm.
3) Often OWNING the boards with his great rebounding.
Losing Freeman WILL hurt for next year, without any real question. His loss may be able to be offset, with a combination of improvement by Omoruyi at PF, and other players at other positions, and HOPEFULLY Shaq Carter being a decent player.