As usual, I will never understand why Wayne Gretzky and era-time-travel issues come up in these topics.
First of all, Gretzky and Ovechkin have NOTHING in common as hockey players, other than they were both dominant in their eras. Gretzky's style of offense was completely unlike Ovechkin's. Gretzky never tried to overpower other players with his shot or (lol!) his physicality. Gretzky almost never (and basically never after about age 24) tried to drive the net in a straight line. Gretzky's entire style of offense was based on avoiding barriers and creating open space for himself and more so for his teammates. Gretzky almost never fired a one-timer in his career. (As a center, Gretzky was primarily a pass-first player, as we all know.)
Second, I could not care less how players of one era would do if "time-traveled" to another era, and neither should anyone. We should not expend any brain-cells on this. Players need to be appreciated in the context of their own eras, period.
Gretzky's peak period was (to be very specific) January 1981 to September 1991. The NHL, and to some extent international hockey, was very different in that period (which is really, in itself, akin to about two mini-eras) from today. Ovechkin, of course, has starred for a very long period (almost 20 years now). Though he's not in his prime by a long-shot anymore, he's still very effective as a scorer.
It's very typically the case with the most elite players in NHL history that they excelled over long and diverse periods. Though Gretzky's prime period was 'only' 10.5 years, this is relative --- he was the highest-scoring N.A. player in 1979-80 and the highest scoring N.A. player in 1997-98, when he was seven years past his prime, old and banged up, and on a very low scoring team. Quite obviously, he could be dominant across different periods and styles of hockey. Same with Howe, Hull, Jagr, etc. Ovechkin has been playing at 'star' level for almost 20 years and has the most insane physical durability of any hockey player ever, or at least since Gordie Howe.
Finally, although I understand the exciting, big-name appeal of a contemporary player beating Gretzky for a major League record, I personally have never thought of the career goals-record as a "Gretzky record". (I'm not sure Gretzky himself does either, and I think he has always had some mixed-feelings about taking that one away from Howe.) To me, the best career / longevity / volume goal-scorers in NHL history (pre-Ovechkin) are Rocket Richard, Bobby Hull, and Gordie Howe. Those guys were dominant as goal scorers for most of their careers, and set the standards for a long and excellent career as goal scorers. Gretzky was more like an "incidental" goal scorer, who was so insanely talented that he racked up 92 and 87 (in 74 games!) goal-scoring seasons while dishing out 130 assists or whatever. He was never a consistently elite goal-scorer after age 26, and essentially an average first-line center in goal scoring from about age 30-31 (though this had a lot to do with accumulated back injuries).
I think it's good if Ovechkin gets the record in as much as the guy with the most seasons leading the League in goals deserves to have the most career goals. Ovechkin seems like a good guy, and obviously the NHL will big-it-up for maximum P.R. value, as it's been so long since any major offensive records have been set or broken. We also know that Gretzky will be all-class about it and first in line to shake Ovechkin's hand.
Anyway, point being -- stop trying to compare players across eras, the more so when the two players aren't remotely comparable. Appreciate the talent of each era.