i seem to be alone on this one, but my memory of the '92-'93 season was that robitaille was the more impressive player, despite the year-end totals. mogilny was certainly the better game-breaker and had miles more talent, and i won't use the "he played with lafontaine" argument because it's not true, but robitaille was phenomenal as LA's alpha dog that year with gretzky and sandstrom out for most of the year, and coffey for half the year. he and kurri (playing out of position at center) absolutely carried that very average kings team, and they made the players around them better-- e.g. granato.
given all the injuries, without robitaille, that team was ray bourque's bruins of the late 80s/early 90s, but without bourque. no way they make the playoffs.
in many ways, what robitaille did that year was a superior version of mogilny's 40 goal year in new jersey, which i thought was mogilny's most impressive year all told: a usually one-dimensional scorer taking the reins and making plays, trying to play a two-way game (though, realistically, he leaned heavily on kurri to take those duties), and being a leader.
another thing to consider is that robitaille's best offensive seasons were without gretzky, '92-'93 and his second year. i think if anything, playing on the same team as gretzky, especially because they rarely played on the same line except on the PP, held him back. he wasn't naturally a take-charge guy, as is well known, and he was more effective playing with carson in a 1a/1b situation with nicholls than as the second option behind gretzky. in his best year, he carries the team all season, then goes back to taking a backseat when gretzky returns and turns in a decent, but not great, playoffs.
all of this, plus of course the longevity and consistency, puts me firmly in the robitaille camp in this poll.