Rooker can't really play left though. He'd probably be Casty-level bad if he did full-time.
The money saved on Rooker versus Schwarber is entirely earned, i.e. he is exactly that much less of a player. And he's not young. And also probably not available. But if he was, I want him on the same team as Schwarber. I think I'd put up with both of them as platoon LF/DH for that kind of pop. But then you've also traded Crawford, among others.
There aren't really that many great 1Bs or DHs out there anyway. I'd rather have Schwarber than any of them including Alonso. Anyway, if you really want to add another guy who can't field, the move would be to put Bryce back in RF. He's a better 1B than Alonso or Hoskins and a better OF than Schwarber or Rooker (low bar).
Bader has also been a pretty poor hitter for the three years before this one. Has he unlocked something sustainable at age 32? Probably not. We already have some inkling of this just from his time in Philadelphia:
352/.410/.544 in his first 37 games with the Phils, but with a .476 BBIP.
In his last 13 games, 192/.236/.269 with a BABIP of .265.
Obviously neither as good nor as bad as those numbers. He's a nice complementary player with good defense. But so is Marsh, and so probably is Crawford. In a perfect world Bader platoons with one of them but he's looking for more money and playing time than that.