Marleau is probably the least impressive player to score 500 goals of all time, if not close.
Marleau playing that many games is only evidence of his health and endurance, not particularly his skill. It’s not like he’s been an elite player for even half of his career, but he hasn’t been terrible, just underwhelming compared to his peers who have played similar amount of games. He had a great 3-4 years where he was a great scoring winger. He isn’t a bad player, I would put him in the “HOVG” but definitely not a HOF worthy talent in my eyes.
700 goals is definitely more impressive and that isn’t debatable. Ovechkin has scored at a 47 goal and 80 point pace since 2015, Marleau at a 22 goal and 47 point pace. Don’t confuse staying healthy with actual top level consistency, even with Marleau, he hasn’t been an impactful player for many years, only good enough.