Time for my write-up of World 3 with my White Mage/Mystic Knight/Geomancer/Red Mage. (EDIT: Dang, this turned out much longer than I expected)
Much of it was a cake-walk thanks to Mobile Geomancer, who was able to use Cave-In in most of the dungeons. And in those dungeons where Cave-In wasn't available, Sonic Boom and Twister did just fine against the non-heavy enemies. This made most of the enemy mobs pretty easy to beat, giving me an incentive to fight all of the battles.
Antlion: Cave-In
Gargoyles: !Spellblade Break on two characters
Pyramid, Sekhmet: Cave-In, Cave-In, Cave-In. None of the mobs stood a chance.
Melusine: Rotating !Spellblade Firaga/Blizzaga/Thundaga, Bindweed and Branch Spear seemed to help out a bit.
Island Shrine: Sonic Boom/Twister most of the non-heavy mobs. Took on Wendigo with !Spellblade Sleep in effect.
Fork Tower was an interesting case. For Minotaur, I sent in my Red Mage and Mystic Knight, both with Elven Mantles. The Mystic Knight would attack with Chicken Knife, while the Red Mage would heal with the Healing Staff. While Minotaur went down without a problem, Omniscient was a bit more tricky. The first time with White Mage and Geomancer, I tried to Berserk him, but he would still cast Return. Couldn't use !Gaia, couldn't attack, etc. So the second time I faced off with him, I decided to put !Spellblade on the Geomancer before the battle. With !Spellblade Silence active, Omniscient couldn't pull off a single spell, while the Air Knife did pretty good damage against him each turn. Thus, I obtained Holy and Flare, giving my White Magic and !Spellblade users some pretty powerful attacks for the rest of the game.
Great Sea Trench: Lots of Cave-In against the mobs. Odin against the Trio, since I could recharge the Magic Lamp here.
I decided to grind at Phoenix Tower for a bit, since I had a Thief's Knife and some Hermes Sandals. Cave-In was not available, so I used a methodical strategy, !Spellblade Sleep on each enemy, whack each enemy with the Thief's Knife to steal their items while maintaining sleep, then finish them off with !Gaia Sonic Boom/Twister when I've got the goods. By the time I made it to the top and back, I had somewhere around 300k worth of Reflect Rings, Rainbow Dresses, and Red Slippers, along with a boatload of ABP from the Magic Pots (The Wonder Wand is great when you only want to expend one Elixir per battle). It was around this time when Lenna learned Dualcast, so I switched her to White Mage so she could make the most of it. That was my plan since getting Red Mage; shoot for Dualcast on one character, and use them as a White Mage for the rest of the game.
Istory Falls: Cave-In and Whirlpool on the mobs. I used that 300k haul to buy four Coral Rings and a fourth Hermes Sandals, so I used the former on Leviathan. Leviathan went down pretty easily with double !Spellblade Thundaga hits from my Mystic Knight and Red Mage.
In the Rift, I ended up running from most mobs, since the !Gaia spells were Sonic Boom/Wind Slash/Twister for most parts. Didn't feel much like fighting the small fries at this point, since time was starting to be a factor
Calofisteri: Double !Spellblade Flare, and a few !Gaia shots with Bindweed and Branch Spear. No problem.
Apanda: Double !Spellblade Firaga, !Gaia Ignus Fatuus, and Dualcast Holy
Azulmagia: Double !Spellblade Flare, Dualcast Holy.
Catastrophe: Same as above. Geomancer was busy with healing the Earth Shaker damage.
Halicarnassus: Went into battle as Frogs to deal with the Ribbit attack. Afterwards, I believe I used a mix of !Spellblade Silence and Flare, along with dualcast Holy.
Twintania: !Spellblade Break while charging for Giga Flare.
Gilgamesh: Stole the Genji Shield with Thief's Knife. Then ended it with a double Holy.
Necrophobe: !Spellblade Break on the Barriers, then double !Spellblade Flare and triple Holy spells on Necrophobe himself. When Gilgamesh appeared, I stole the Genji Armor off him.
So, all that was left was Exdeath himself. I put Enhancers on my Spellblade users, Hermes Sandals on 3 out of 4 party members, Genji Armor on Mystic Knight Faris, Mirage Vest on Red Mage Bartz, and set off. Exdeath was an easy battle, as I started off by ticking down his MP with double !Spellblade Osmose hits. He got off a few White Holes, but they were easy enough to heal with Dualcast Esuna/Arise. The point of this battle was to prepare for the next phase, so I took his MP down to nothing, and spent some time buffing everyone with Protect/Shell/Blink from White Mage Lenna and Krile the Geomancer. When I was ready, I switched Bartz to !Spellblade Break and Faris is !Spellblade Flare, and let loose on Exdeath.
A defenseless Exdeath eventually led to Neo Exdeath, so I kicked off the trippy battle by popping the Magic Lamp a few times. Bahamut/Leviathan/Syldra to damage all four parts, Odin to take out the bottom-left part, all the way down to Golem for physical protection. Then I used Bartz to Break the bottom-right part, and switched him to Flare. The timing worked out, since Neo Exdeath ended up using Grand Cross a bit later; no major problems, Bartz was Berserked (Which worked out, since all he would need to do at that point was attack), Lenna was Doomed, while Krile and Faris were blinded (I healed Faris with Esuna). With two parts left, I decided to spread the damage out evenly, so I'd alternate targets with Dualcast. With three Holy spells and two Flareblades per turn, the middle part fell, and the front part soon followed it in the nick of time, with only 7 seconds remaining on Lenna's Doom timer. #Victory!
So, some final thoughts on this run, since it's my first time through the mobile version, some thoughts on that too. The last time I had to use Geomancer was in my first Fiesta, way back in 2011. I remember being pleasantly surprised by it then, it wasn't a fantastic class, but it was quite useful in certain situations. This time, playing on the mobile release, Geomancer almost borders on overpowered. You see, in the other versions, !Gaia attacks are determined by RNG using two ranges; first is the up to four quadrants for each terrain, with each quadrant corresponding to a specific attack, second is your character level, which serves as the upper bound for the RNG (e.g. if your character level is 21, the RNG will pick a number between 1 and 21). The mobile version takes character level out of the equation entirely, so it essentially picks a number between 1 and 99. This means that in the mobile version, the high-level !Gaia spells (51-99) are now available from the start.
This makes a huge difference for the Geomancer's usefulness, as now !Gaia can summon powerful spells like Cave-In (4x random hits for 500-3000 damage), Twister, and Earthquake from the get-go, eliminating plenty of mobs and bosses, depending on the terrain. I guess it is offset by the fact that even with the whole range unlocked, some of the common roadblocks (Soul Cannon, Archeoaevis, Crystals, W2 Exdeath, most of the Rift Bosses, Neo Exdeath) are still major threats, due to their heavy status and a lack of powerful !Gaia attacks for their terrain. So in a way, Geomancers are still pretty balanced out.
That's probably the biggest point I got out of this run, as I've had the other jobs more often. White Mage is a fantastic support who turns into a late-game heavy-hitter, Mystic Knight is still a great utility player, and Red Mage... Well, outside of Dualcast, next time I draw RM, I'll just have to remember to pick up plenty of FIL Rods from Karnak before leaving World 1.
As for the rest of the mobile release, once I got past the ugly character sprites, I enjoyed it quite a bit. It felt pretty much the same as the GBA version gameplay-wise, outside of some minor tweaks/bugfixes here and there. The interface worked well enough for touch, and I didn't have any problems navigating dungeons with the virtual stick. The only noticeable issue that I ran into was at the very end, when the music for the Neo Exdeath battle and credits didn't sync up with some usual on-screen cues. And, of course, it was nice to have an easy method of taking screenshots.