Re Gau vs. Iga:
I don't know how much speed AtL2 PCs lose in 6 levels (given how small the curve is, it can't be that much), but I just tried removing Diekbeck and stripping 3 speed off of the two PCs you mentioned. I got an average of 23.47 and a SD of 1.90, which would put Iga at +0.17, which is 2.55% to you I believe?
By the numbers in the FF6 stat topic, Gau can beat that just by opting for a Tiger Mask (even assuming everyone else switches to their best +speed helmet and adjusting the average). With your SD views he can even survive a pretty significant FF6 speed disrespect. With Dark Gear all doubt is removed, though of course he'd need to have a strategy which can survive his now below average defence (Charm should work).
Re status balancing:
Another issue which you may or may not want to factor in which certainly makes a big difference is enemy durability. It's really hard to care about most status in a game where enemies tend to get 1-2HKOed by almost all damage anyway. (Sometimes this combines with "lots of immune enemies" where only the real fragile ones are vulnerable... e.g. almost everything you can ID in Shadow Hearts 3 has low enough HP that they can be OHKOed by ordinary magic, thus Grand Slam is pathetic in-game.)
You're right that, under my views, a cast with nothing but statusblockers benefits tremendously. (Or, alternatively, a cast whose statusblockers are on their overall best equips anyway... such as Chrono Trigger, or FF5 PCs with access to Ribbons.) I don't really have a big problem with this, because it tends to mean you do use statusblockers in-game in those games, so those PCs do feel more intuitively status-resistant. By comparison you don't want to use basic statusblockers much in FF6 because you're pushing out some really useful things. I do agree it does inflate some casts, but there is some logic behind it, and it really isn't any different from the way FF9/Legaia 2/etc. benefits from its elemental defence.
Speaking of, if anyone knows of any games where you are basically sure that status hits all randoms at same hits rates (basically meaning nothing is immune), please let me know!
Games with randoms who are uniformly status-susceptible? The list strikes me as fairly short. Running down the list of ranked games...
-Fire Emblem, but this isn't DL relevant for the most part.
-Legend of Dragoon, IIRC
-Phantasy Star 4 has Explode/Negatis/Crash which hit all species types (only failing on bosses), although their rates do vary with the target's strength/magic stat. Other status is species-restricted, though you can at least predict what status will and won't work on typically.
-Pokemon (with only extremely rare exceptions in gen 3 onwards)
-Seiken Densetsu 3, IIRC? If there are immune randoms I'm blanking on them, maybe those clones in the final dungeon... Wouldn't be surprised if SoM were the same.
-Suikoden 1, for ID at least
-Valkyrie Profile 1 is pretty close, only a few boss pallette-swaps are immune, though those do become common right at the end.
-I believe KOS-MOS' S-Chain works on pretty much all randoms, and many bosses.
There may be more since I'm not an expert on the status attacks of every DL game. Obviously there are also moves which just work on
everything (Spellbinding Eye, FF6 Charm, WA4 stat downs outside magic immunity) but those tend to get more respect as is.
