A
Link to the Past. I think they called it that just for the sake of making a pun.
Also, since AoL was such a radical departure from LoZ, the game may well have been called "to the past" to emphasize that it had it's origins in LoZ (the past) rather than the more recent AoL. Basically, to let you know they were largely going back to their previous Zelda formula. IOW, they may have meant OUR past rather than Hyrule's past.
So I guess it was a combination of a desire to make that Link pun, and the desire to emphasize that the game was connected to LoZ rather than AoL (since a lot of people didn't like AoL).
They might well have originally planned to bill it as an updated version of LoZ, so they might have considered titles like "Super Legend of Zelda," or "The Legend of Zelda: A Blast from the Past." When those names were rejected because they wanted something a little more serious-sounding and relevant to the series, they just decided to be clever and go, "Fine. How about A Link to the Past? That does have his name in it, and sounds fairly serious." Then everyone laughs, thinks its catchy, and it sticks.