I disagree. Geos for Mages, maybe... but they have twice the MDef and less vulnerability to fire. For swordies, you need like 142 HIT to hit them 100% of the time, meaning that even at level 60 most swordies/knights wouldn't hit Geographers reliably.
Geographer = 8071 HP, 26+83 MDef, 150% vulnerable to fire, 142 to HIT 100% :: 13575/10000 Base EXP/Job EXP
Increase Soil = 8230 HP, 12+23 MDef, 200% vulnerable to fire, 116 to HIT 100% :: 13800/10550 Base EXP/Job EXP
I'd say that makes soils better, so long as you can keep them away (mages can just move and cast, swordies can use the trick above). This is all just my opinion, though, so people can go to Geos instead, obviously