And either way, if there's a crowd of archers in the next room I wouldn't want to walk in (sneaking or no) where I have no cover, so I'm going to try and hold at the door. Still the better play even if it costs a whole turn of not being able to use my action.
The missing Ready action really tilts things toward those "alpha strike" characters made to hit first and hit hard, which isn't a design choice I like much. I want to be able to lure enemies into a room with minor illusion or other sounds and have the whole party readied the jump them.
The ready action is designed to get used for delaying actions to bypass initiative order.
Speaking of delay, I know that's not part of 5e (it was in 3.5), but if we can't have ready action could we at least have the delay option? A lot simpler to implement and it'd at least help with the situations where you would have been better off at worse initiative.