A) That's a very different discussion that what the op was getting into.
B) The areas where scaled back to give a distinct theme yes in part, but they aren't bigger than are because of memory issues as well. All those thematic pieces take up memory and that directly limits the size of the map. Just because a thematic reason was listed doesn't for a second change the 512mb limit of the system that directly limits area sizes. Did you ever wonder why Coerthas was the biggest map? Have you ever noticed it has less overall detail than the other maps since it's mostly white snow and rocks? There is a trade off.
So? Yoshi also said they have plans to drop it sometime after the first expansion pack based upon current usage and upgrade statistics.
They've repeatedly said the UI can't be expanded anymore on the ps3 due to memory issues.
Every new feature that is big they've mentioned ps3 issues.
It's not just design decisions holding the game back. You need to remember that those design decisions are made in part due to the memory limitations. You can't separate them into two different things because they are intrinsically connected.
Those graphical assets take up memory. Which the ps3 is very low on. Add too many beards and now the average character requires more polys and therefore more memory. Graphical assets must take up ram to be used so any assets that add to memory directly contribute to the problem. Try to remember that they shrunk miq'ote butts for two reason. One was so that making new gear was easier across races, but if I remember correctly it was also mentioned that it helped put more on screen at once. That would be due to fewer poly's being used. Beards would be like bringing those butts back.
Doesn't matter what FFXI did here since inventory is a server memory issue. The only way it's limited on the system is how many inventory slots can be displayed at once. Even FFXI had to split inventory into multiple different types of inventory in order to manage all that inventory on the limited system memory of the ps2.
You are very severely underestimating memory issues across the board when it comes to the ps3 and how those limits affect nearly everything about this game.