It's kind of unnecessary to add anything here, but I will anyway. For one thing, hearing loss in one ear doesn't much affect perception of stereo balance, since so much of the sound is mixed with reflections by the time it arrives at your head. Try closing off one ear and listening to speakers; then disconnect one channel of a set of headphones and see what happens! Needless to say, two functioning ears for stereo listening, like two functioning eyes for stereoscopic vision, is necessary for the illusion of soundstage, depth, and so on, but it's not as if your left ear hears the left speaker and your right ear hears the right speaker—as is the case, of course, with headphones.
Second, IMO a balance control is an essential thing; in fact, a powered balance control you can adjust from the sweet spot on the fly is highly desirable. Getting the balance just right at the sweet spot is crucial for a realistic soundstage, and must be fine-tuned with each recording. This is because listening to the illusion of 3D produced by two stereo speakers is not the same as sitting in a concert hall; being off-center in a concert hall is no where near as destructive of that illusion as being off-center to speakers. This is a matter of physics; as Jim Smith puts it (tip #83, re: the impossibility of a wide sweet spot): "this is an incontrovertible law of physics that is part of the good—and the bad—of stereophany. It has no bearing whatsoever upon sitting off-center in the concert hall, because the sound is not being reproduced from a pair of widely spaced loudspeakers which are subject to severe comb filtering due to varying time arrivals at your head."