The issue with WOWY is that you get a chart that treats all player combinations equally, while most of them have so few solid minutes together that you can't draw any conclusions from them. RelTM offers the exact same thing, but aggregates the results and weighs them according to how much time they spend on the ice. Therefor, what Nylander does with Matthews is of much more importance than what ice time he gets along with someone that he is just out there for a few shifts with.
I'm not sure what this had to do with using RelTM instead of WOWY? Either way, you can use xGF% for that.
Oh, and LA has been the best defensive team of the decade and has been a dominant CF% team.
Nylander led the team in passes to high-scoring areas at even strength. His shot spread doesn't support your anecdote either, as he doesn't take more low danger shots than normal.
Furthermore, what drives CF% is ability to transition, sustain pressure, and create shot opportunities. If someone throws pucks on net like you describe, they'd just get one-and-done opportunities before the puck goes the other way, which would lead to bad shot metrics.
Like I said above, RelTM is WOWY but aggregated and weighed for the ice time factor.