I remember a lot of people being critics back then, but then again I grew up just outside of Edmonton, and lots of people were huge fans, which naturally means there were some very vocal detractors as well. I remember my one uncle, who was a huge Hull fan, constantly complaining about Gretzky being small, slow, weak, etc. He complained a lot about how Gretzky'd never won anything. That was obviously before their first cup. He and my other uncle (who was a Gretzky fan) would debate endlessly about the topic.
One has to remember that early on, Gretzky had won Bronze in the world Jrs, Edmonton had lost the last Avco cup to Winnipeg, Canada had lost 8-1 to the Soviets in the 81 CC, and then when Edmonton got swept by the Islanders, it really did look like he was a great offensive star who put up tons of regular season points, but couldn't get it done when it really mattered. Of course, from there he'd go on to win 4 cups in the next 5 years, take LA to a cup finals with them, win golds in the 84, 87, and 91 Canada Cups, leading every one of these playoff and tournament runs in points, and end up being probably the greatest playoff performer of all time. But prior to all the wins, there were plenty of critics. I'm sure there were still critics afterwards, but once he'd won 4 cups they were a lot more quiet. Or at least my one uncle was, and so were the kids I knew in school who didn't like him (though to be fair, they were pretty scarce to begin with).