Quickleaf
Legend
That's exactly it right there.You might be able to get away with a shorter, snappier spell description if you can somehow remove all the rules lawyers or have players willing to accept DM fiat without question. For example, "loudly" is an imprecise term. Loud like a tea kettle, a lawnmower or a bulldozer? Audible to anyone in the room or in the dungeon? One DM might interpret loudly as "can't be done from Stealth", another as "you've just put the whole complex on high alert".
Most of the provisos are designed to either reign in abuse from players (well, a castle is a type of container, knock should open the portcullis) or to be used by the DM as a way to appeal to authority from the rule book itself (no, a container is...) Should that be the way the rule book works? Probably not, but everyone has a bad player/DM story where the outcome bordered on the precise language of the spell or power in question.
Brevity may be the soul of wit, but D&D is closer to contract law than poetry.
Me saying "loudly" is as functionally useful as the PHB saying "a loud knock, audible from as far away as 300 feet", it's just I took fewer words to say it.
My experience is that most people have no frame of reference for what a sound "audible from as far away as 300 feet" is comparable to, nor how such a sound would interact with being in an underground complex.
Your comparing it to something players would have a frame of reference for would be functionally more useful. Though probably terms like a "train whistle" or a "jet engine" would feel anachronistic, with a little thought something suitably faux medieval could be used like "loudly, like an elephant's call" or "as loud as a trumpet."