Sorcerers quicken is the only real place where the BA restriction makes sense and needs to be in place; outside of that it just creates unnecessary restriction and some fairly asinine weirdness - If you poke around some of my other posts on the subject, I make a few examples of how the rule formally works in 5e, what that means, and why it's generally ridiculous and silly - and worse, unfairly crippling and limiting of classes that don't deserve it (point in case for those folks who think I'm a 5e-defending zealot across the board - there are numerous places where it handles things poorly, or has bad rules, and this is one of them).
