As was noted, Gordie Howe scored 44 goals at age 40, but that was mainly due to mass expansion shortly before. Still very impressive, though.
The Caps' 20th-place finish in offense last season was their lowest placing since 2006 (though 2011 was close, at 19th). I don't follow the Caps enough to know how good / bad they are, but I think if they're depending on Dylan Strome to be their top center, then they're in for a tough season offensively. And a team struggling to win gets few empty-net opportunities (for Ovi to score).
Still, there's the PP. The Caps maintained a more-or-less League-average PP last season, so if they can do that again, Ovi will get his goals. If he can manage around 14-15 PP goals next season, then even a decline at ES from, say, 28 to 20, would still give him about 35 goals on the season.
I say, around 35.