I remember in the first a few version of the game full attack was using offhand recovery time, but currently in 5.0 I found that my full attacks are using mainhand weapon to calculate recovery, anyone know when this is changed? Thanks!

Hmm actually I'm wrong, it is not using either mainhand or offhand, it is using the slower recovery of your weapon for full attack recovery now...

I think that was done because players (smartly) put a weapon + slow modal (like +2 PEN or Bleeding Cuts) into their main hand and then something fast (dagger or such) into the offhand - then did only Full Attacks. With Bleeding Cuts that's a special kind of cheese since it's damage increase is very high (also because the DoT instances stack) and is only balanced somewhat by the horrendous recovery malus - which was circumvented entirely with the "old" Full Attack implementation. 

I frequently suggested to use Battle Axes that way and was recently surprised that it doesn't work anymore.

Yeah. They are great as a Retaliation weapon though... if you can trigger lost of ripostes/retaliation attacks.

 

Well, the combo of Rapier with its +20 Accuracy modal plus regular one-handed is still good. Rapier's recovery with the modal is almost the same as a slower one-handed weapon without one. And if you main hand a heavier hitting weapon, frequent rapier crits will trigger Swift Flurry/HB Drumming main hand attacks, which do much better damage then a rapier.