I agree that Ovechkin is the best goal scorer currently and maybe of all time. However, for the reasons you stated I think Crosby is the better all around player. If you were an expansion team 5 years ago when Ovi and Crosby were in their prime and you could select one of them who would you take. I think you have to take Crosby.
I probably would too, from the standpoint of picking one player to build a team around. With Crosby I'd feel comfortable playing him with mid-level players and he'd figure out how to get things done. With Ovechkin I wouldn't feel great without an elite Center feeding him and another player to dig out pucks for him, since I'd want Ovi in shooting position all the time.
That said, what Ovechkin does best is more difficult than what Crosby does best. A lot of people might point to Crosby's superior point per game pace, but scoring is simply more difficult (plus two assists for every goal means a playermaker
should have more points than a goal scorer). As a playmaker you just have to find an open man among the other 4 guys on the ice with you. As a goal scorer, everyone knows where you are and what you're capable of. To still be able to score despite what other teams are doing to defend against you is an impressive feat.
It's more common to find a player of Crosby's skillset than it is to find one of Ovechkin's. McDavid is already better than Crosby. But Ovechkin's closest competition, Patrik Laine, is too inconsistent right now. And none of the other top goal scorers this year are perennial threats for the Rocket - they just have the occasional "career year." Ovechkin has won the Rocket 7 times as leading goal scorer. His only losses were when he had abnormally "down" years, and that one year where he lost by one goal but also played 10 less games than everyone else. No one else has won the goal scoring lead more than twice in the past two decades. Meanwhile, the Art Ross, which probably favors a player who can rack up points via assists, has been won twice by four players in the past 2 decades (including Crosby).
Don't get me wrong, I'd rather have Crosby skating around all over the ice making an impact and playing a 200 foot game. I don't particularly trust Ovechkin to defend/backcheck, or carry the puck in (he'll try some overused deke and lose it), or battle along the boards. But Ovechkin dominates in his field moreso than Crosby does in his field. Nobody scores like Ovechkin, and of the guys who are close, none bring half the physicality Ovechkin does. But I could name a handful of Crosby comparables.