I mostly bolded for my own reading, as I tend to jump around a little bit, I'm not picking apart those specific sentences as a forewarning. Helps me hit your main points (as I see them, feel free to point out anything I didn't address as I'm not attempting to cherry pick you're argument)
I'll be clear and say I do not have any issue looking at PPG when you're evaluating the players, all other things being equal. My main argument was that you're putting to much weight into it for those specific seasons at least.
PPG vs Point finishes is a pretty clear cut area IMO, because I find final results more impressive than extrapolating numbers. Its like when people argue Lemieux is better than Gretzky overall in my mind, sure when he played there is a definite argument that Lemieux was a better player for one reason or another. The only issue is, Gretzky was at that level for much longer and having a larger body of work (when the comparison is close) does get my credit.
I don't see it as career "value" as much as career impact, though it could be splitting hairs. My main issue that I detract for not only malkin, but all players that lose time to injury often in their career (Lemieux, Orr, Lindros, Forsberg, Malkin, Kariya as some examples compared to their respective peers) is that when they are in the game they are having a larger impact on the game if they scored or not compared to if they were in the press box.
When you're looking at a season by season comparison like your first post, games played is a larger factor considering it is a small sample size to begin with. You only have so many opportunities to make an impact, that if you miss 20 games its a big hamper to your resume (for that particular season). When you go into your example over an entire career, I'm leaning towards agreeing with you (though there are some very limited information) that if it was just based on those two, with the one with more seasons/less games having higher ppg MAY have been better. IF the player that had less games hadn't won awards, and the player with full seasons had then its a different story. My big issue with not only this, but hypotheticals in general, is that its always a case of "what if" and a rabbit whole of statements prefaced as such.
I would definitely say I find it impressive that Malkin does have hardware, but in context of who they played with it holds less weight to me. Yzerman in particular having the highest amount of points of anyone not named Gretzky or Lemieux in a season holds as much weight as one art ross to me.
Malkin adding longevity, even if its 5 more 60-70 game seasons, if he plays as well as he has would definitely put him above sakic. Yzerman is a tougher one for me to say, but malkin could definitely get there potentially. Yzerman is definitely more subject to the mystical and stat defying leadership and defensive abilities in his late career, as well as his complete 180 from offense only to one of the best two way centers of all time. I try and avoid arguing "but he was captain!!!111!", but leadership does hold weight because its not easy, its not for everyone, and a good or bad captain does effect a team greatly.
IF both sakic and malkin had 800 games played, then yes I'd say PPG can weigh into the argument more heavily (though there is more to give credit for defensive play to sakic) but you're mixing reality with hypotheticals and, again, I'm not a huge fan of hypotheticals. If you keep malkins PPG the exact same and he had 1000 games played more or less, I'd definitely be more inclined to say malkin is better. But he doesn't, so in my opinion hes not at this point in time.
My issue with Sakic 94 vs. Malkin 15, is that in the end its the same result for points (its not extremely far off). Sure malkin played better in a per game basis, but overall I'd rather have Sakic on the ice and not getting a point than having Malkin in the press box having an AHL call up take his spot on the roster. I honeslty can't fault you for liking malkins season more.
I don't think sakics season adds more or malkins season adds more to be quite honest, their essentially passenger seasons on their career as a whole and I think thats where the issue is. My main argument is for sakic or against malkin. I don't think malkins season adds more simply because results, in the end, matter and neither really does Sakics. Neither alone are impressive, neither won awards, and neither really gets the ticker going. Sure 7th in ppg is impressive, but the guy already won a couple art ross trophies. Does it really matter all that much that he had another season in which he could have been better if he'd played more? The difference between the two players isn't so little that one higher PPG season at this point in time.