After the recent reputation recalc I noticed my reputation had dropped about 1K and the vast majority of that came from the deletion of really old questions. And by really old I mean questions that had survived for over 2 years.
I hate to use the word unfair but I'm struggling to find a better way to describe the situation. On one hand I completely understand both the need to keep the site clean and for moderators to be able to override the majority vote. On the other hand the current system is basically asking users to predict future trends in moderation and punishing them if they're wrong.
For example I had a mildly popular answer on one of the recently deleted questions. I think I got 30-40 upvotes on the first day and then less than 1 vote per week for the next 2 years. The latter part was not a significant part of any days rep for me after the first day. But over a 2 year time span the cumulative effects added up. When the question was deleted I was rewarded with a nice fat single day -662.
Again, I understand the need to delete bad data from the site. But I think you need to balance the removal of bad data with the negative effects it has on people who are contributing. I propose a small change to this process to help balance the scales a bit.
If a question is < 6 months old leave the process unchanged. If it's over 6 months delete the question but leave the reputation gained / lost from it unchanged. Don't punish the people contributing due to a future change in what is thought to be productive / unproductive on the site.