Tarasenko. If you're willing to wait 2 years he'll be better than anyone selected behind Hall and Seguin. With your deep farm you can also afford to take the risk. Also if you're going to trade down I'd trade into the Jeff Skinner range, that kid is going to be a star.
If you pick relatively soon again after this pick then go with Vladimir. You'll get one of the guys like Skinner or Watson that others might skip on taking. So you'll get a relatively sure thing in one of them and a possible home run in Tarasenko. Not to say that Connolly or Johansen won't be good as well, but I just don't see them having quite the same upside in Johansen's case or durability in Connolly's case.