hi pallandrone
the time someone needs strongly depends how much it is polished. FFTA (I think you are talking about advance) is for example a game which has top-notch graphics. Also the designs are very unique and there are lots of pieces, maybe things you don't even have thought of.
make first a rough list of the workload:
Icons:
-about 200 item icons
-some other icons
Menu Art:
-menu designs, map designs, map icons, menu icons
-intro art
-faces (about 55 pieces, non-ppixel art, but very well drawn and clear for their resolution)
tiles&animation
-about 60 maps (somewhat of 35 unique tilesets)
-about 15 monster sprites
-34 common chars (about 40 frames per)
-~8 unique chars (up to 80 frames, emotions ... call 'em heros)
weapon paperdolling (saves a bunch of time)
-atk&effect gfx
most of this is non-pixel art, but very detailed and with lots of frames, great effects.
As you see there is a bunch of stuff. If you start with your own game, you also have to calculate lots of time for designs and stuff which won't make it in the game, you can't build in everything.
Icons:
-about 200 item icons - at least 15min/piece = 50h
-some other icons (class icons, bubbles, craft icons, HUD icons, map icons about 100 pieces) - 20min/piece = 25h
Menu Art:
-menu design
-map designs
-misc stuff (buttons, small icons, arrows ...)
-textboxes
really hard to say, calculate somewhat of about 60h
Intro
-intro art
depends on how much you do, storyboarding the font, animations, length... and ... all other you need
-faces (about 55 pieces, non-pixel art, but very well drawn and clear for their resolution) about 4h for each (= 220h)
tiles&animation
-about 60 maps (somewhat of 35 unique tilesets) with good planning + reuse, about 20h per map, all together maybe 1000h
-about 15 monster sprites (50 frames) about 10h per piece (=150h)
-34 common chars (about 40 frames per) about 8h (270h)
-~8 unique chars (up to 80 frames, emotions ... call 'em heros) calculate 20h per hero, they need lots of personality, lots of concepts, need to be appealing... 160h
weapon paperdolling (saves a bunch of time)
-atk&effect gfx
most of this is non-pixel art, but very detailed and with lots of frames, great effects. With about 300h all is sure
50h icons
25h icons
60h menu art
xh intro
220h faces
1000h all the maps
150h monster sprites + animations
270h common chars
160h heros
300h effects
total about 2250h - very tight calculated, if you do your first calculations with about 3000h of a graphical workload It's doable.
They also had 15 artists just for drawing. If you calculate it with 15 artists, and a 40h week of work everybody would have worked 5 weeks. I don't know how long it was in development and how much of the artists worked in the core-graphic team. but if you calculate with 8 artists, you'd need about 10 weeks, which is with a development time of about a year for a gba game is relative realistic.
Another thing you have to keep in mind is that you really need some specailists to create a game in this quality, I don't think you will find anyone who is.
For a huge workload like this a coordinator and art-director is also necessary, otherwise the graphics/styles will clash, it's a huge work to coordinate the stuff.
If you find anyone who thinks he can create a game like it on his own, i'd say you have someone who is really self-confident, plain unexperienced or overestimating himself really.
If it's a top-notch project like FFTA think with a team, it's not doable with a team smaller than 5 really motivated people - and even with a small team you have far a long development time.