I know what you mean by this, but bear in mind that in terms of Tarasenko's ability to put pucks on net (shots, through%), his ability to score at even-strength, and his ability to set up teammates by drawing coverages, there are very, very, very few players in the league today that do what Tarasenko does. In some ways, the things you're saying about Tarasenko are the exact same in substance as what can be said about someone like Gaudreau (although his schtick obviously isn't physicality or size). The thing about those high-flying offensive talents is that they take a ton of attempts that go nowhere and fail. It's a numbers game though, if you shoot enough it's going to go in eventually. Guys like Tarasenko and Gaudreau generate that volume better than most, which makes those sometimes frustrating failures tolerable. It comes with the territory.
So, yes defenses have gotten better about dealing with Tarasenko, but along the way he's adapted as well, which is why his production is staying steady. Yes, you'd like to see improvement, but there just aren't many if any players who are doing that in the way that Tarasenko is. It's easy to pick on him when he makes mistakes, or when he hits a cold streak and the mistakes start to pile up. So, I don't really care if he is or isn't laying people out (in fact I'd prefer he didn't), as long as Tarasenko is being Tarasenko, there's no reason to worry.