The Capitals made the playoffs 16 times during Ovechkin's career, and went 8-8 in the first round. That's somewhat disappointing given that Washington finished with more points in the regular season in 12 out of those 16 series, but not terrible.
What really looks bad is the team's 1-7 record in second round series. They finished with more points than their opponent (in the regular season) in 6 of those 8 series, so that's quite a poor outcome.
Overall, if we assume that the team with the higher seeding in the regular season was the favourite to win the series (an oversimplification, of course), Washington should have gone something like 18-6 in the first two rounds. (A better way to do the analysis would be to calculate the expected wins/losses for each series - that would have a flatter outcome, something like 15-9). In reality, they went 9-15. Regardless, the Capitals clearly underachieved in the playoffs over the past 20 years. (But - and this is important - we need to do a deeper dive, rather than ascribe all of this to Ovechkin. He certainly cost the Capitals some series with no-show performances, but there were also quite a few series that they lost, despite him playing excellent hockey).
