Well for starters the MSQ in 4.3 blows 3.1 out of the water. The trial is actually farmable by pugs unlike Thordan, and the 24 man is relatively challenging this time around. Not only that but there's actually more stuff to do in general. Crafters and gatherers got a bunch of new things to do aside from the Namazu, we got a new roulette which breathes life into dead content.

4.3 is far greater than 3.1 in terms of substance, taking into consideration the dead on arrival Verminion and Diadem becoming Dino Island on day 2.

Now let's look at the .3x series as a whole, even though you said no. What we got between 3.1 and 3.2 were the anima weapons, that's it, and were you around for that initial i210 step? It was absolute hell. In comparison we're getting a new ultimate encounter, another post 60 levelling method, and a new stage of Eureka. It might be delayed, but it's something.