I don't really think Hayward has nearly as much value as we think given his huge contract number next year and his ability to leave the year after. Couple that with his significant injury concerns, and I don't know what his value actually is. That said, I don't think Hayward, Langford, and 14 for Turner and Oladipo is that much of a stretch given Oladipo is unhappy, has injury concerns himself, and will almost certainly leave Indiana after the year. So Oladipo and Hayward are very similar (except Oladipo is unhappy). Turner is expendable for the Pacers and everyone knows it, so I don't think his value is that great either, which is why I think that trade could potentially happen. But Indiana is one of the few places that would see Hayward as more than expiring contract/rental type situation. Anywhere else, and I really don't think Hayward has that much value.
As for the trade, I probably wouldn't do it because I don't think Collins is good enough to really count on being my long term center and the C's don't need another mid to late round 1st. Now if I had some other trade lined up where I needed some good sized expiring contracts and another 1st round pick, then I might be willing to do it.