OK, having played TAY in full.. I have something to say (in a more educated way anyways).
I think that compared to the original game, it's on par with the type of development of the original... which that is, it's good enough, but there's some serious plotholes or issues and some under-development.
For instance, in FF4, Rosa is underdeveloped (and I don't mean boobies) in terms of character. Other than that she cares for Cecil, she's kinda one-dimensional... unlike Rydia. In TAY, we continue the same theme, except she's covered up like she's gotten really old (she's like twice her age in the TAY storyline)... and Rydia shows everything off (unmarried, then again, Edge must be taking some long route or Rydia is really playing hard to get). Did I miss something there?
How does Shiva manage to kill the Dark Elf? Her special attack is far inferior to the Particle Bomb band (or Bio for that matter), yet the Dark Elf is known to have a wicked high magic defense... WHAT THE HELL?
Then again, does anyone expect Luca's Dolls to say anything worthwhile? I guess being the reincarnation of Chuckie and his bride is good enough... although IMO they are truly clones of Palom and Porom if they were made super crack fighters (which they are).
There's issues of balance for that matter... why make Cid really obsolete? He's simply damn slow and his special isn't even boss-friendly... why even bother with the moon phases at that point?
Calca's Jive skill is obsolete by the time you can actually use the dolls.. then again, they are likely underleveled compared to the rest of the characters. If only Brina's Dance would produce more favorable results (or at least, controllable results)...
Harley is useless, from both a story and character standpoint. First off, making her not a Blue Mage makes her worthless... plus it's the only time where I find Gil Toss to be powered by INT (seriously, it is) outside of STR and AGI. I don't get it. She's gotta be stealing money away from Edward's Kingdom... it shouldn't be that easily possible to go bankrupt the way they do. Maybe Edward buys extravagant gifts... but even then, Harley's useless where it matters most... on the battlefield. Edward is an upgrade to Harley... and that's not saying much (the only useful band is Feast of the Land).
For characters that already have character... they got more development.. like Palom and Porom (to some degree), but Ceodore is a disgrace. At least Kain salvages this as that character development is at least a reasonable plotted course...
In the end, it's more of the same... and the same shit that was there before is still there, more shit. It's still enjoyable by the game's relative stands and I think the band system is an improvement given what there is to work with, and in some ways, makes it enjoyable (do Ice Crush enough, and you'll laugh). Although, I cannot explain the Weapon in Progress band nor the Rapid Fire band. I don't really see the connection. Although, with the spying ninjas, you can actually see logically created bands based off who they spied which are actually very good despite the strangeness of them at times.
The moon phases... allows for some interesting stuff, but in their own ways can be annoying. They only matter when you want to dish damage...
I'll say more when it comes to it, but ultimately it's more of the same, and fighting monsters that were easily kicked in the ass in the original is kinda lame (at least, make it interesting). The FF1A-like add-on monsters are not really that interesting to me and neither are the superbosses, other than kicking their ass and then some (well, the only boss that was a true challenge was Nova Dragon aka Shinryu).