Ovechkin is still great but Kucherov is a superstar in his prime. It's not fair to Kucherov to bring him down because of 1 playoff series where the whole team sucked. He's not the first and won't be the last great player to get shut down in 1 series. 4 games (well, he only played in 3) is a very small sample size. I mean, if Tampa completed the comeback in game 4, and get a spark as a team, Kucherov could just as easily have a 3 point game in the next one and end up with 5 pts in 5 games as he had 2 apples to begin with.
Overall i've thought Kucherov has been good in the playoffs throughout his career. Most of the time Tampas most dangerous forward. He's a skill player and when the opposing team succeeds in shutting him down, he doesn't bring a whole lot which makes it look like the classic "no show". But that's the way it usually goes for skill wingers who aren't physically dominant. When it's not working they look soft, when it's working feels like they can create magic out of nothing plays. Heck, there's been times in Ovechkin's career when he's almost looked like a black hole offensively 5v5 in the playoffs.
Anyway, i thought 16/17 was the season when Kucherov hit a new level. Numbers weren't as flashy since Tampa wasn't a playoff team that year, but since that season he has 313 points in 236 games. Also 120 goals. He's basically a 40 goal, 100+ point guy at this point in terms of expectations. Ovechkin is still the best goalscorer in the league, and does bring grit, but he hasn't hit 90 points in literally 10 years.
The way i see it i'd be almost disrespectful to Kucherov if i didn't give him the credit he deserves, he's the best winger in the game right now. Playoffs, if anything, is a team effort.
But it's close, stats from this season definitely don't reflect the difference between the two. Still, if 128 points isn't enough to give the mantle of best winger in the game then i don't know what is.