Dave Bautista has been adamant this is his last Marvel movie and has kind of bad mouthed the Drax role in several interviews, so it wouldn't shock me if Drax dies.
He has definitely said this is his last turn as Drax, but I wouldn't say that he bad mouthed the role so much as saying that it is kind of silly and he wants to do more serious roles. Although I guess that's why you said "kind of".
Also, there has been speculation for a while that Rocket would die in the 3rd one... so my money is Drax and Rocket dying.
I don't think they'll do it, but I think it would be kind of epic if they all went down together, as a family.