To better illustrate the maps issue, the pre-release has about a quarter less maps of the final release, yet still takes up the same amount of space, if not more.
Similar nickel-and-diming for free bytes is present in the location events as well. Three debug bytes removed per event, and some frequently used 2 byte event commands were given 1 byte variants.
At the time (Q4 1994), 32 megabits was just becoming a reality in games like Donkey Kong Country. It would've been simply too expensive at the time for a 48 megabit cart. ToP wasn't until a year later.
Even if there was more space, time was still an issue. How much additional content was ready and could've been added (and beta tested) before the 3/11 release? From what I can gather, there was simply no way they were going to budge from that date (which had been heavily advertised for months and months) and they were just barely able to meet that deadline.
I think if they squeezed every last drop out of the remaining free space in the 32 megabit and their deadline, the final game could've had the 3 lost beta dungeons: Singing Mountain, Zeal dungeon, and Forest Ruins. In TF, for example, 4 Forest Maze maps (the largest compressed map) can be imported without expansion.
Again, given the time to optimize, the full, uncut Ted Woolsey translation could've fit as well.
Anyway, whenever I see this topic it makes me wonder what the game, like Secret of Mana, might have been like if the SNES CD was released.