More or less true. But a lot of players suffer because they don't get the chance to play everyday... I'm sure you could come up with a wealth of players who turned from mediocre to good or great players after getting the opportunity to play everyday (i.e. Bautista).
Are you kidding? Take away Melky's '12 and their career stat lines are basically the same. I also presume Melky starting taking PED's in '11... so you should probably take that out of the equation too, in which case Snider is an overall BETTER offensive player than Melky. And imagine if he had the opportunity to play everyday. Plus we already know Snider will provide better defense. So how the f*** can't you compare them?