I agree Head is more valuable than Snyder and JL3. And heck, I'd trade those two for peanuts just to free up roster spots and clear the books if possible. Head right now is TMac's backup. That is a fine roll for him. Right now we have 4 guards who were productive last year Tmac, James, Alston and Head. Brooks can be in the mix, but he is unproven. Snyder and Wells, giving their jumper range limitations, foremost should compete for back up SF minutes (Reed and Novak can have their opp too, but I am doubtfull). Head still has decent value, at least late 1st round quality where he was taken. Quite honestly because of his age, contract and productivity, he has more trade value than Snyder, Wells, Alston and James. I would be open to trading Head only if it was part of securing a decent PF/PF prospect (like Ike, one of Atlanta's excess PFs, Brian Cook, etc).
I watched him play last year. He doesn't belong in the NBA anymore. He'd be gone already if there weren't a new coach. The new coach will see it soon enough.