Rojas didn't sit especially often either way. He made 54 starts, 36 against RHP and 18 against LHP. I honestly just didn't realize that he was hitting RHP "better" (.592 OPS vs. .489, while also presumably being PH for against RHP sometimes).
Pache did make 19 starts against LHP (this will be his second against a RHP) but only 10 of those were in CF.
Had Rojas been able to hit LHP at a .700 OPS clip (which is about what Pache does) his overall number would have looked a lot better. Probably can't expect him to ever top .600 OPS against RHP unless it's with bunts and IF singles.
Like the Phillies said, it's a better team with Rojas. We'll see if they mean it.