@Yerachmeal
White won't retreat the bishop to f4 but rather to h4 keeping the pressure. And before you rush the bishop is not trapped. Also in the position you just showed black king is exposed and white has a clear plan. There is a reason d5 and Nf6 is played more.
Retreat to h4 and black is still fine.
In the position I showed before, white's king and the pieces near it are under a lot of pressure too.
@d4iscrazy
Adopting the slav set up against the catalan kills the catalan bishop and the game will be closed and boring with maneuvers. Perfectly playable for black and no black doesn't have to defend. It's an equal game.