I think the rehashed zones are more a reflection of the slim dev team rather than any limitations. My opinion though.
I played on the PS2 since it came out and only switched to PC in the last few months. Why? Because SE does NOT CURRENTLY support the PS2. Oh sure they do on paper. Sure they include updates for it as well. But what most, if not all, PS2 players can tell you, the game does not run properly on PS2 at all anymore. SE has not fixed the problem and refuses to acknowledge that it is a problem. I switched to PC when I realized I couldn't teleport to whitegate from sandy, I couldn't OP warp from sandy, I could not continue the CoP, ToAU, WotG, or ACP missions because the cutscenes did not work. I never bought abyssea because other PS2 users often complained of zoning into maws crashing their systems. So no missions, no abyssea, sketchy interactions with NPCs. This is the result of no support.
What would we get by dropping the ps2? Probably an even further reduced dev team that can't implement any new features.
Major graphics overhaul will not happen. If SE drops the ps2 they will lose some players. Maybe not tons but some at least. If the do a major graphics update they will lose even more from the number of people that can no longer play because they are on older PCs that can't handle the new updates. Sure new graphics might draw in new people but if there is one thing SE (at least in the USA) is horrible at, it is advertising. And remember they are still hoping FFXIV will take off. They aren't trying to attract new players to this game.
Plus enjoy all my typos because I have to run and don't have time to read through this again!