I disagree. Whilst maybe not "great", Meaney always stood out to me as a very capable, talented player at the Dogs. he was good, and better than anyone gave him credit for. His time at both Newcastle and Canterbury were in terrible teams. But that doesn't change the fact that he himself was always a very good player. Just as an example, take Jacob Liddle. Do you think other fans other than our own rate him as a pretty good player? No, because they aren't watching closely and he's not in a good side. Yet, we can see he's a very good dummy-half. You can make the same argument you make about Meaney with Liddle. Put him in a good system and he'll shine much more. That's the same with any player ever to play the game.
What I'm saying is that he doesn't just "look" much better than before. He was always a very good player, playing in awful teams. it's hard to stand out as a good player when your teams are getting battered every week. The Dogs completely undervalued him too which didn't help. As you say, given an opportunity in a good system that has actually recognised his ability has shown what he can do. Mind you, Melbourne aren't that good this year, yet he's standing out.
Main point is, he was in two of the worst teams in the last 10-15 years of rugby league, and as soon as he gets out of that environment into a decent team, he's a stand out. Very good player.