I've never liked "Break the Rules" either. I'm talking specifically of the people saying its chance of making an impact on radio is up. Despite finding it mediocre as a song I do think its radio-readiness is quite clear and that the album pushback is therefore not that confounding.
In this commercial climate it's not at all unreasonable for the label to hope for two hit singles before the album's release date, especially if one of those singles is already available on a successful soundtrack to a summer blockbuster. "Boom Clap," having gone #1 on US pop radio, probably did exceed their expectations as far as audience penetration goes, and it's taking its sweet time to depart from heavy rotation at most stations. The timing for the "Break the Rules" radio rollout is reasonable and stations will probably be receptive enough to at least make it a moderate hit. Given all that, it isn't really that horrifying that the album was delayed... and by what, a month? This is clearly not becoming some sort of Sky Ferreira situation. It's not even becoming a Becky G situation. The album will probably come out with few issues and do just fine.