Rubio didn't punch for six in his fight with Lemieux, than he (Lemieux, who was 22 then) gassed. Rubio tried to exchange with Golovkin and we know the result. But you are right about picking GGG at this point of Lemieux career (and maybe at anypoint).
GGG took a lot of flush punches from Stevens (relative to ability) so I'm not 100% gonna say Lemeiux can't catch him But saying that, in also thinking GGG intentionally took those shots from Stevens due to the pre-match talk - to show him he can take his shots - also to set himself up too. But it could also be a weakness in the kazakh's armoury
GGG. He will punch in between Davids hooks, get there quicker and walk him down. Lemieux's power comes from him stepping into his power punches giving him a lot of leverage......going backwards is a skill he hasn't yet mastered and Golovkin will be making him fight off the back foot. David has power to make GGG think ..... But GGG also has power that will make David revert back to the early days where he mentally falls apart when things are not going to plan. I expect HBO and David's handlers to talk the fight with GGG up, but maneuver around him until they've miked David against some opposition that will be made to order.....where he will look great, build his brand, win a title and set up a big fight with GGG down the road.
In other words, you believe the Lemieux from last Saturday is the same Lemieux who Rubio stopped in 2011. No credibility whatsoever, champ. "If" his eye held up? Well "if" Rosado chose to exchange more often Lemieux would have knocked him out. Point is, you don't know that. Fact is, Lemieux broke Rosado's orbital rim with a single left hook. You can "if" it all you want. Terrible defense, check. Not terrible, but well below average. Below average accuracy and speed, disagree. Once he got past Rosado's jab, he had decent accuracy in the pocket. He couldn't have landed that much had he had slow hands - he doesn't. Can't take a punch to save his life - based on what exactly? If you didn't see improvements from the Rubio fight with his conditioning and pacing, you just don't know what you're watching.
Lemieux has potential, he already has a potent offense, but fighting a Quillin, Korobov, Cotto, or Lara would help to clarify at what level he's really at.