If the ice-time that's missing is PP time, you'd be pretty stupid not to think that the player's production wouldn't increase with increased PP time.
Linemates argument though? It's subjective in every aspect.
The reverse is true if its even strength time that's missing. Or PK time...Linemates is about chemistry, some stars just don't play well together because they each need to drive the play. Problem is both arguments are technically subjective. Subjectively, would a guy player better with a better linemate, or subjectively, would a guys increased ice-time be guaranteed to be PP time? In both cases you have to make assumptions.
Problem I have with the second scenario, is that you are assuming that a coach doesn't know to a pretty good estimate, what a players optimal ice-time is. A coach should probably be questioned if he's playing a guy 18 minutes a night who is a star player, but would produce more at 23 minutes a night. That's really poor utilization of a player, my only conclusion must be that he knows the player will not produce more, or will produce more in the short term and then be utterly useless by game 70.
The thing about a hockey season is that the best a player can hope to do is maintain his weight and muscle mass. They cannot gain mass throughout the season unless they are eating poorly, because the strength training aspect of their regiment is largely eliminated when they practice/condition everyday and play 3-4 times a week. You can't lift heavy weights and be recovered in time for games, this is why offseason training is so important. So where is the precedent for players who should have a lot of trouble physically improving themselves throughout the season, to suddenly begin taking on 15-20%+ more physical wear during games (toi)?
EDIT - It took Klefbom 4 years to become comfortable with his current ice time. They spoke about it in the game last night, he said he used to feel gassed after 19 minutes of ice time, now he is playing ~25mins per night (he's also not running and gunning like a forward). Evidence suggests that any increase in this department is gradual, or not at all.
NOTE - I'M NOT TALKING ABOUT ANY PLAYERS IN PARTICULAR, ice-times are just estimates.