I did it this way because it was the easiest. It would take a long time to figure out how much the shares were diluted in which rounds and to calculate how much each person should get. Also, on average those rounds had about 300,000 devcoins, more than people are getting this round, so those in the previous rounds are already getting plenty.
Edit: Since people want more to be sent to the previous rounds, in the next payment I'll send according to the round 28 account file, instead of the round 32 file.
Easiest way is just ask notabot for a ballpark % activity by round. That way there's no competing biases, what happens happens and we all move on.
Edit: didn't notice your time consuming point. Then I'd just take the current list (to exclude anyone since removed for deserved reasons) and split it evenly. Anything coming is probably more than expected so not worthy of much complaint imo. It's a group endeavour so if people want precise re-distribution let them spend time calulating it all.