A late reply but you guys replied to everything already 
:
- Yes the battery is bigger, but 20 milliampere-hour is not a game changer (@urs_lesse is right) ;
- As @paulakreuzer rightly guessed, the battery had to be revised because of a change of supplier, not because we tried to make it different;
- @BertG and @Patrick1 outlined that already, there is only so much power you can pack in a defined volume. We certainly did not want to change the phone design and hence had to work with the same constraints than for the original battery: we needed a drop-in replacement to keep supporting all Fairphone 2 out there.
- @BertG also expressed the fact there are performance variations between batches, and considering that we are looking at a whopping bump of less than 1% nominal capacity, let’s say that one should not expect to notice anything based on that;
- If anything, the tuning can make a difference. Let’s see what your feedback is once the batteries are available .
Thanks guys