I love the miscommunication thing! It allows for some very interesting character introspection, especially with Alec and his guilt. It´s also nice to have a scene between him and Clary where they are genuinely nice to each other and Clary is reassuring him.
This episode did a fantastic job humanizing Maryse! Before this she was kinda just... awful? And now I feel really bad for her. Like we know her relationship with Izzy isn´t great, and now we know she willingly took on that tension so Izzy wouldn´t be hurt.
To be fair, there were a few indications that Clary might be interested in Simon. Like last episode she was kinda jealous about Simon having a date, and she was staring at him while he was putting his shirt on. But.... yeaaah he still feels clearly like the 2nd choice after Jace wasn´t an option anymore.
Izzy´s situation just keeps getting worse, but its great that Raphael is now involved in it, even if he is potentially just making things even worse by enabling Izzy.