It's not even close, Piazza is a clearly better hitter than Bench. (And probably just as clearly not as good of a player as Bench, don't get me wrong). He was terrible at throwing runners out, I don't think he was as bad at the other stuff, but definitely not a great or even good defensive catcher.
If you're asking me if I think Piazza used PEDs, I would say he probably did. But I would still vote for him.
Let's just look at guys who were voted in by the writers, cause the veterans list is a bit of a joke.
I would vote Raines over these guys: Jim Rice, Ralph Kiner, Lou Brock, maybe Harry Heilman (I'm blocked from baseball reference, so I can't do as much research as i'd like), maybe Willie Keeler, he played a million years ago, who knows.
If you look at the vet committee guys, he blows a ton of them away.
Fangraphs WAR has Raines as the 31th best OF of all time. 5 or 6 of those guys aren't in or aren't eligible, so he's something like a top 25 OF, if you like WAR. (Which you probably don't, since you don't have him in).
Raines would be 6th on the list of guys I gave.