This inconsistency stuff irks me re: Kreider & Zibanejad; someone of the broadcast crew last night, (which, by the way, was absolutely awful collectively...), kept bring it up when commenting on Kreider. Both players have the attributes to plainly dominate games like that. This doesn't mean that when they aren't dominating they are in turn playing poorly. There is statistical evidence of the two having had a long-term, hugely positive impact on the Rangers when they're on the ice.
You can call the fact that Kreider doesn't "dominate" or score 4 points every game, by definition, "inconsistency", but there is no facet of hockey I can think of that is not inconsistent. It's a deeply chaotic sport that takes place 1, 271+ times NHL every year.
Edit: also, things always look worse when the puck isn't going in, (or vice versa if you're looking at defense re: goaltending).