No, a lot of people have confirmed it's not going to be strictly 3-4 and that Wade, nowadays, is running a unique hybrid defense.
A quote from Wade himself
"We try to fit what the players can do in the defense rather than saying, 'OK, we're a 4-3 or we're a two-gap 3-4,'" Phillips said per The Denver Post. "We're a team where if a guy can stunt and rush the passer, we let him do that. If a guy is a power guy, we try to let him be that. It's all what individual players can do."
Basically, Wade will use a scheme that fits his players. Will have a touch of Wade's uniqueness to it, I'm sure. Expect them to be a top 5 D, maybe not next season, but in 2018.